1 /*
2 * Copyright (c) 1994, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.lang.annotation.Annotation;
29 import java.lang.constant.ClassDesc;
30 import java.lang.constant.ConstantDescs;
31 import java.lang.invoke.TypeDescriptor;
32 import java.lang.invoke.MethodHandles;
33 import java.lang.ref.SoftReference;
34 import java.io.IOException;
35 import java.io.InputStream;
36 import java.io.ObjectStreamField;
37 import java.lang.reflect.AnnotatedElement;
38 import java.lang.reflect.AnnotatedType;
39 import java.lang.reflect.AccessFlag;
40 import java.lang.reflect.Array;
41 import java.lang.reflect.Constructor;
42 import java.lang.reflect.Executable;
43 import java.lang.reflect.Field;
44 import java.lang.reflect.GenericArrayType;
45 import java.lang.reflect.GenericDeclaration;
46 import java.lang.reflect.GenericSignatureFormatError;
47 import java.lang.reflect.InvocationTargetException;
48 import java.lang.reflect.Member;
49 import java.lang.reflect.Method;
50 import java.lang.reflect.Modifier;
51 import java.lang.reflect.RecordComponent;
52 import java.lang.reflect.Type;
53 import java.lang.reflect.TypeVariable;
54 import java.lang.constant.Constable;
55 import java.net.URL;
56 import java.security.AllPermission;
57 import java.security.Permissions;
58 import java.security.ProtectionDomain;
59 import java.util.ArrayList;
60 import java.util.Arrays;
61 import java.util.Collection;
62 import java.util.HashMap;
63 import java.util.LinkedHashMap;
64 import java.util.LinkedHashSet;
65 import java.util.List;
66 import java.util.Map;
67 import java.util.Objects;
68 import java.util.Optional;
69 import java.util.Set;
70 import java.util.stream.Collectors;
71
72 import jdk.internal.constant.ConstantUtils;
73 import jdk.internal.loader.BootLoader;
74 import jdk.internal.loader.BuiltinClassLoader;
75 import jdk.internal.misc.Unsafe;
76 import jdk.internal.module.Resources;
77 import jdk.internal.reflect.CallerSensitive;
78 import jdk.internal.reflect.CallerSensitiveAdapter;
79 import jdk.internal.reflect.ConstantPool;
80 import jdk.internal.reflect.Reflection;
81 import jdk.internal.reflect.ReflectionFactory;
82 import jdk.internal.util.ModifiedUtf;
83 import jdk.internal.vm.annotation.AOTRuntimeSetup;
84 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
85 import jdk.internal.vm.annotation.IntrinsicCandidate;
86 import jdk.internal.vm.annotation.Stable;
87
88 import sun.invoke.util.BytecodeDescriptor;
89 import sun.invoke.util.Wrapper;
90 import sun.reflect.generics.factory.CoreReflectionFactory;
91 import sun.reflect.generics.factory.GenericsFactory;
92 import sun.reflect.generics.repository.ClassRepository;
93 import sun.reflect.generics.scope.ClassScope;
94 import sun.reflect.annotation.*;
95
96 /**
97 * Instances of the class {@code Class} represent classes and
98 * interfaces in a running Java application. An enum class and a record
99 * class are kinds of class; an annotation interface is a kind of
100 * interface. Every array also belongs to a class that is reflected as
101 * a {@code Class} object that is shared by all arrays with the same
102 * element type and number of dimensions. The primitive Java types
103 * ({@code boolean}, {@code byte}, {@code char}, {@code short}, {@code
104 * int}, {@code long}, {@code float}, and {@code double}), and the
105 * keyword {@code void} are also represented as {@code Class} objects.
106 *
107 * <p> {@code Class} has no public constructor. Instead a {@code Class}
108 * object is constructed automatically by the Java Virtual Machine when
109 * a class is derived from the bytes of a {@code class} file through
110 * the invocation of one of the following methods:
111 * <ul>
112 * <li> {@link ClassLoader#defineClass(String, byte[], int, int) ClassLoader::defineClass}
113 * <li> {@link java.lang.invoke.MethodHandles.Lookup#defineClass(byte[])
114 * java.lang.invoke.MethodHandles.Lookup::defineClass}
115 * <li> {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
116 * java.lang.invoke.MethodHandles.Lookup::defineHiddenClass}
117 * </ul>
118 *
119 * <p> The methods of class {@code Class} expose many characteristics of a
120 * class or interface. Most characteristics are derived from the {@code class}
121 * file that the class loader passed to the Java Virtual Machine or
122 * from the {@code class} file passed to {@code Lookup::defineClass}
123 * or {@code Lookup::defineHiddenClass}.
124 * A few characteristics are determined by the class loading environment
125 * at run time, such as the module returned by {@link #getModule() getModule()}.
126 *
127 * <p> The following example uses a {@code Class} object to print the
128 * class name of an object:
129 *
130 * {@snippet lang="java" :
131 * void printClassName(Object obj) {
132 * System.out.println("The class of " + obj +
133 * " is " + obj.getClass().getName());
134 * }}
135 *
136 * It is also possible to get the {@code Class} object for a named
137 * class or interface (or for {@code void}) using a <dfn>class literal</dfn>
138 * (JLS {@jls 15.8.2}).
139 * For example:
140 *
141 * {@snippet lang="java" :
142 * System.out.println("The name of class Foo is: " + Foo.class.getName()); // @highlight substring="Foo.class"
143 * }
144 *
145 * <p> Some methods of class {@code Class} expose whether the declaration of
146 * a class or interface in Java source code was <em>enclosed</em> within
147 * another declaration. Other methods describe how a class or interface
148 * is situated in a <dfn>{@index "nest"}</dfn>. A nest is a set of
149 * classes and interfaces, in the same run-time package, that
150 * allow mutual access to their {@code private} members.
151 * The classes and interfaces are known as <dfn>{@index "nestmates"}</dfn>
152 * (JVMS {@jvms 4.7.29}).
153 * One nestmate acts as the
154 * <dfn>nest host</dfn> (JVMS {@jvms 4.7.28}), and enumerates the other nestmates which
155 * belong to the nest; each of them in turn records it as the nest host.
156 * The classes and interfaces which belong to a nest, including its host, are
157 * determined when
158 * {@code class} files are generated, for example, a Java compiler
159 * will typically record a top-level class as the host of a nest where the
160 * other members are the classes and interfaces whose declarations are
161 * enclosed within the top-level class declaration.
162 *
163 * <p> Unless otherwise specified, methods in this class throw a
164 * {@link NullPointerException} when they are called with {@code null}
165 * or an array that contains {@code null} as an argument.
166 *
167 * <h2><a id=hiddenClasses>Hidden Classes</a></h2>
168 * A class or interface created by the invocation of
169 * {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
170 * Lookup::defineHiddenClass} is a {@linkplain Class#isHidden() <dfn>hidden</dfn>}
171 * class or interface.
172 * All kinds of class, including enum classes and record classes, may be
173 * hidden classes; all kinds of interface, including annotation interfaces,
174 * may be hidden interfaces.
175 *
176 * The {@linkplain #getName() name of a hidden class or interface} is
177 * not a {@linkplain ClassLoader##binary-name binary name},
178 * which means the following:
179 * <ul>
180 * <li>A hidden class or interface cannot be referenced by the constant pools
181 * of other classes and interfaces.
182 * <li>A hidden class or interface cannot be described in
183 * {@linkplain java.lang.constant.ConstantDesc <em>nominal form</em>} by
184 * {@link #describeConstable() Class::describeConstable},
185 * {@link ClassDesc#of(String) ClassDesc::of}, or
186 * {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}.
187 * <li>A hidden class or interface cannot be discovered by {@link #forName Class::forName}
188 * or {@link ClassLoader#loadClass(String, boolean) ClassLoader::loadClass}.
189 * </ul>
190 *
191 * A hidden class or interface is never an array class, but may be
192 * the element type of an array. In all other respects, the fact that
193 * a class or interface is hidden has no bearing on the characteristics
194 * exposed by the methods of class {@code Class}.
195 *
196 * <h2><a id=implicitClasses>Implicitly Declared Classes</a></h2>
197 *
198 * Conventionally, a Java compiler, starting from a source file for an
199 * implicitly declared class, say {@code HelloWorld.java}, creates a
200 * similarly-named {@code class} file, {@code HelloWorld.class}, where
201 * the class stored in that {@code class} file is named {@code
202 * "HelloWorld"}, matching the base names of the source and {@code
203 * class} files.
204 *
205 * For the {@code Class} object of an implicitly declared class {@code
206 * HelloWorld}, the methods to get the {@linkplain #getName name} and
207 * {@linkplain #getTypeName type name} return results
208 * equal to {@code "HelloWorld"}. The {@linkplain #getSimpleName
209 * simple name} of such an implicitly declared class is {@code "HelloWorld"} and
210 * the {@linkplain #getCanonicalName canonical name} is {@code "HelloWorld"}.
211 *
212 * @param <T> the type of the class modeled by this {@code Class}
213 * object. For example, the type of {@code String.class} is {@code
214 * Class<String>}. Use {@code Class<?>} if the class being modeled is
215 * unknown.
216 *
217 * @see java.lang.ClassLoader#defineClass(byte[], int, int)
218 * @since 1.0
219 */
220 @AOTSafeClassInitializer
221 public final class Class<T> implements java.io.Serializable,
222 GenericDeclaration,
223 Type,
224 AnnotatedElement,
225 TypeDescriptor.OfField<Class<?>>,
226 Constable {
227 private static final int ANNOTATION= 0x00002000;
228 private static final int ENUM = 0x00004000;
229 private static final int SYNTHETIC = 0x00001000;
230
231 private static native void registerNatives();
232 static {
233 runtimeSetup();
234 }
235
236 /// No significant static final fields; [#resetArchivedStates()] handles
237 /// prevents storing [#reflectionFactory] into AOT image.
238 @AOTRuntimeSetup
239 private static void runtimeSetup() {
240 registerNatives();
241 }
242
243 /*
244 * Private constructor. Only the Java Virtual Machine creates Class objects.
245 * This constructor is not used and prevents the default constructor being
246 * generated.
247 */
248 private Class(ClassLoader loader, Class<?> arrayComponentType, char mods, ProtectionDomain pd, boolean isPrim, char flags) {
249 // Initialize final field for classLoader. The initialization value of non-null
250 // prevents future JIT optimizations from assuming this final field is null.
251 // The following assignments are done directly by the VM without calling this constructor.
252 classLoader = loader;
253 componentType = arrayComponentType;
254 modifiers = mods;
255 protectionDomain = pd;
256 primitive = isPrim;
257 classFileAccessFlags = flags;
258 }
259
260 /**
261 * Converts the object to a string. The string representation is the
262 * string "class" or "interface", followed by a space, and then by the
263 * name of the class in the format returned by {@code getName}.
264 * If this {@code Class} object represents a primitive type,
265 * this method returns the name of the primitive type. If
266 * this {@code Class} object represents void this method returns
267 * "void". If this {@code Class} object represents an array type,
268 * this method returns "class " followed by {@code getName}.
269 *
270 * @return a string representation of this {@code Class} object.
271 */
272 public String toString() {
273 String kind = isInterface() ? "interface " : isPrimitive() ? "" : "class ";
274 return kind.concat(getName());
275 }
276
277 /**
278 * Returns a string describing this {@code Class}, including
279 * information about modifiers, {@link #isSealed() sealed}/{@code
280 * non-sealed} status, and type parameters.
281 *
282 * The string is formatted as a list of type modifiers, if any,
283 * followed by the kind of type (empty string for primitive types
284 * and {@code class}, {@code enum}, {@code interface},
285 * {@code @interface}, or {@code record} as appropriate), followed
286 * by the type's name, followed by an angle-bracketed
287 * comma-separated list of the type's type parameters, if any,
288 * including informative bounds on the type parameters, if any.
289 *
290 * A space is used to separate modifiers from one another and to
291 * separate any modifiers from the kind of type. The modifiers
292 * occur in canonical order. If there are no type parameters, the
293 * type parameter list is elided.
294 *
295 * For an array type, the string starts with the type name,
296 * followed by an angle-bracketed comma-separated list of the
297 * type's type parameters, if any, followed by a sequence of
298 * {@code []} characters, one set of brackets per dimension of
299 * the array.
300 *
301 * <p>Note that since information about the runtime representation
302 * of a type is being generated, modifiers not present on the
303 * originating source code or illegal on the originating source
304 * code may be present.
305 *
306 * @return a string describing this {@code Class}, including
307 * information about modifiers and type parameters
308 *
309 * @since 1.8
310 */
311 public String toGenericString() {
312 if (isPrimitive()) {
313 return toString();
314 } else {
315 StringBuilder sb = new StringBuilder();
316 Class<?> component = this;
317 int arrayDepth = 0;
318
319 if (isArray()) {
320 do {
321 arrayDepth++;
322 component = component.getComponentType();
323 } while (component.isArray());
324 sb.append(component.getName());
325 } else {
326 // Class modifiers are a superset of interface modifiers
327 int modifiers = getModifiers() & Modifier.classModifiers();
328 if (modifiers != 0) {
329 sb.append(Modifier.toString(modifiers));
330 sb.append(' ');
331 }
332
333 // A class cannot be strictfp and sealed/non-sealed so
334 // it is sufficient to check for sealed-ness after all
335 // modifiers are printed.
336 addSealingInfo(modifiers, sb);
337
338 if (isAnnotation()) {
339 sb.append('@');
340 }
341 if (isInterface()) { // Note: all annotation interfaces are interfaces
342 sb.append("interface");
343 } else {
344 if (isEnum())
345 sb.append("enum");
346 else if (isRecord())
347 sb.append("record");
348 else
349 sb.append("class");
350 }
351 sb.append(' ');
352 sb.append(getName());
353 }
354
355 TypeVariable<?>[] typeparms = component.getTypeParameters();
356 if (typeparms.length > 0) {
357 sb.append(Arrays.stream(typeparms)
358 .map(Class::typeVarBounds)
359 .collect(Collectors.joining(",", "<", ">")));
360 }
361
362 if (arrayDepth > 0) sb.append("[]".repeat(arrayDepth));
363
364 return sb.toString();
365 }
366 }
367
368 private void addSealingInfo(int modifiers, StringBuilder sb) {
369 // A class can be final XOR sealed XOR non-sealed.
370 if (Modifier.isFinal(modifiers)) {
371 return; // no-op
372 } else {
373 if (isSealed()) {
374 sb.append("sealed ");
375 return;
376 } else {
377 // Check for sealed ancestor, which implies this class
378 // is non-sealed.
379 if (hasSealedAncestor(this)) {
380 sb.append("non-sealed ");
381 }
382 }
383 }
384 }
385
386 private boolean hasSealedAncestor(Class<?> clazz) {
387 // From JLS 8.1.1.2:
388 // "It is a compile-time error if a class has a sealed direct
389 // superclass or a sealed direct superinterface, and is not
390 // declared final, sealed, or non-sealed either explicitly or
391 // implicitly.
392 // Thus, an effect of the sealed keyword is to force all
393 // direct subclasses to explicitly declare whether they are
394 // final, sealed, or non-sealed. This avoids accidentally
395 // exposing a sealed class hierarchy to unwanted subclassing."
396
397 // Therefore, will just check direct superclass and
398 // superinterfaces.
399 var superclass = clazz.getSuperclass();
400 if (superclass != null && superclass.isSealed()) {
401 return true;
402 }
403 for (var superinterface : clazz.getInterfaces()) {
404 if (superinterface.isSealed()) {
405 return true;
406 }
407 }
408 return false;
409 }
410
411 static String typeVarBounds(TypeVariable<?> typeVar) {
412 Type[] bounds = typeVar.getBounds();
413 if (bounds.length == 1 && bounds[0].equals(Object.class)) {
414 return typeVar.getName();
415 } else {
416 return typeVar.getName() + " extends " +
417 Arrays.stream(bounds)
418 .map(Type::getTypeName)
419 .collect(Collectors.joining(" & "));
420 }
421 }
422
423 /**
424 * Returns the {@code Class} object associated with the class or
425 * interface with the given string name. Invoking this method is
426 * equivalent to:
427 *
428 * {@snippet lang="java" :
429 * Class.forName(className, true, currentLoader)
430 * }
431 *
432 * where {@code currentLoader} denotes the defining class loader of
433 * the current class.
434 *
435 * <p> For example, the following code fragment returns the
436 * runtime {@code Class} object for the class named
437 * {@code java.lang.Thread}:
438 *
439 * {@snippet lang="java" :
440 * Class<?> t = Class.forName("java.lang.Thread");
441 * }
442 * <p>
443 * A call to {@code forName("X")} causes the class named
444 * {@code X} to be initialized.
445 *
446 * <p>
447 * In cases where this method is called from a context where there is no
448 * caller frame on the stack (e.g. when called directly from a JNI
449 * attached thread), the system class loader is used.
450 *
451 * @param className the {@linkplain ClassLoader##binary-name binary name}
452 * of the class or the string representing an array type
453 * @return the {@code Class} object for the class with the
454 * specified name.
455 * @throws LinkageError if the linkage fails
456 * @throws ExceptionInInitializerError if the initialization provoked
457 * by this method fails
458 * @throws ClassNotFoundException if the class cannot be located
459 *
460 * @jls 12.2 Loading of Classes and Interfaces
461 * @jls 12.3 Linking of Classes and Interfaces
462 * @jls 12.4 Initialization of Classes and Interfaces
463 */
464 @CallerSensitive
465 public static Class<?> forName(String className)
466 throws ClassNotFoundException {
467 Class<?> caller = Reflection.getCallerClass();
468 return forName(className, caller);
469 }
470
471 // Caller-sensitive adapter method for reflective invocation
472 @CallerSensitiveAdapter
473 private static Class<?> forName(String className, Class<?> caller)
474 throws ClassNotFoundException {
475 validateClassNameLength(className);
476 ClassLoader loader = (caller == null) ? ClassLoader.getSystemClassLoader()
477 : ClassLoader.getClassLoader(caller);
478 return forName0(className, true, loader);
479 }
480
481 /**
482 * Returns the {@code Class} object associated with the class or
483 * interface with the given string name, using the given class loader.
484 * Given the {@linkplain ClassLoader##binary-name binary name} for a class or interface,
485 * this method attempts to locate and load the class or interface. The specified
486 * class loader is used to load the class or interface. If the parameter
487 * {@code loader} is {@code null}, the class is loaded through the bootstrap
488 * class loader. The class is initialized only if the
489 * {@code initialize} parameter is {@code true} and if it has
490 * not been initialized earlier.
491 *
492 * <p> This method cannot be used to obtain any of the {@code Class} objects
493 * representing primitive types or void, hidden classes or interfaces,
494 * or array classes whose element type is a hidden class or interface.
495 * If {@code name} denotes a primitive type or void, for example {@code I},
496 * an attempt will be made to locate a user-defined class in the unnamed package
497 * whose name is {@code I} instead.
498 * To obtain a {@code Class} object for a named primitive type
499 * such as {@code int} or {@code long} use {@link
500 * #forPrimitiveName(String)}.
501 *
502 * <p> To obtain the {@code Class} object associated with an array class,
503 * the name consists of one or more {@code '['} representing the depth
504 * of the array nesting, followed by the element type as encoded in
505 * {@linkplain ##nameFormat the table} specified in {@code Class.getName()}.
506 *
507 * <p> Examples:
508 * {@snippet lang="java" :
509 * Class<?> threadClass = Class.forName("java.lang.Thread", false, currentLoader);
510 * Class<?> stringArrayClass = Class.forName("[Ljava.lang.String;", false, currentLoader);
511 * Class<?> intArrayClass = Class.forName("[[[I", false, currentLoader); // Class of int[][][]
512 * Class<?> nestedClass = Class.forName("java.lang.Character$UnicodeBlock", false, currentLoader);
513 * Class<?> fooClass = Class.forName("Foo", true, currentLoader);
514 * }
515 *
516 * <p> A call to {@code getName()} on the {@code Class} object returned
517 * from {@code forName(}<i>N</i>{@code )} returns <i>N</i>.
518 *
519 * <p> A call to {@code forName("[L}<i>N</i>{@code ;")} causes the element type
520 * named <i>N</i> to be loaded but not initialized regardless of the value
521 * of the {@code initialize} parameter.
522 *
523 * @apiNote
524 * This method throws errors related to loading, linking or initializing
525 * as specified in Sections {@jls 12.2}, {@jls 12.3}, and {@jls 12.4} of
526 * <cite>The Java Language Specification</cite>.
527 * In addition, this method does not check whether the requested class
528 * is accessible to its caller.
529 *
530 * @param name the {@linkplain ClassLoader##binary-name binary name}
531 * of the class or the string representing an array class
532 *
533 * @param initialize if {@code true} the class will be initialized
534 * (which implies linking). See Section {@jls
535 * 12.4} of <cite>The Java Language
536 * Specification</cite>.
537 * @param loader class loader from which the class must be loaded,
538 * may be {@code null}
539 * @return class object representing the desired class
540 *
541 * @throws LinkageError if the linkage fails
542 * @throws ExceptionInInitializerError if the initialization provoked
543 * by this method fails
544 * @throws ClassNotFoundException if the class cannot be located by
545 * the specified class loader
546 *
547 * @see java.lang.Class#forName(String)
548 * @see java.lang.ClassLoader
549 *
550 * @jls 12.2 Loading of Classes and Interfaces
551 * @jls 12.3 Linking of Classes and Interfaces
552 * @jls 12.4 Initialization of Classes and Interfaces
553 * @jls 13.1 The Form of a Binary
554 * @since 1.2
555 */
556 public static Class<?> forName(String name, boolean initialize, ClassLoader loader)
557 throws ClassNotFoundException
558 {
559 validateClassNameLength(name);
560 return forName0(name, initialize, loader);
561 }
562
563 /** Called after security check for system loader access checks have been made. */
564 private static native Class<?> forName0(String name, boolean initialize,
565 ClassLoader loader)
566 throws ClassNotFoundException;
567
568
569 /**
570 * Returns the {@code Class} with the given {@linkplain ClassLoader##binary-name
571 * binary name} in the given module.
572 *
573 * <p> This method attempts to locate and load the class or interface.
574 * It does not link the class, and does not run the class initializer.
575 * If the class is not found, this method returns {@code null}. </p>
576 *
577 * <p> If the class loader of the given module defines other modules and
578 * the given name is a class defined in a different module, this method
579 * returns {@code null} after the class is loaded. </p>
580 *
581 * <p> This method does not check whether the requested class is
582 * accessible to its caller. </p>
583 *
584 * @apiNote
585 * This method does not support loading of array types, unlike
586 * {@link #forName(String, boolean, ClassLoader)}. The class name must be
587 * a binary name. This method returns {@code null} on failure rather than
588 * throwing a {@link ClassNotFoundException}, as is done by
589 * the {@link #forName(String, boolean, ClassLoader)} method.
590 *
591 * @param module A module
592 * @param name The {@linkplain ClassLoader##binary-name binary name}
593 * of the class
594 * @return {@code Class} object of the given name defined in the given module;
595 * {@code null} if not found.
596 *
597 * @throws LinkageError if the linkage fails
598 *
599 * @jls 12.2 Loading of Classes and Interfaces
600 * @jls 12.3 Linking of Classes and Interfaces
601 * @since 9
602 */
603 public static Class<?> forName(Module module, String name) {
604 Objects.requireNonNull(module);
605 Objects.requireNonNull(name);
606 if (!ModifiedUtf.isValidLengthInConstantPool(name)) {
607 return null;
608 }
609
610 ClassLoader cl = module.getClassLoader();
611 if (cl != null) {
612 return cl.loadClass(module, name);
613 } else {
614 return BootLoader.loadClass(module, name);
615 }
616 }
617
618 /**
619 * {@return the {@code Class} object associated with the
620 * {@linkplain #isPrimitive() primitive type} of the given name}
621 * If the argument is not the name of a primitive type, {@code
622 * null} is returned.
623 *
624 * @param primitiveName the name of the primitive type to find
625 *
626 * @jls 4.2 Primitive Types and Values
627 * @jls 15.8.2 Class Literals
628 * @since 22
629 */
630 public static Class<?> forPrimitiveName(String primitiveName) {
631 return switch(primitiveName) {
632 // Integral types
633 case "int" -> int.class;
634 case "long" -> long.class;
635 case "short" -> short.class;
636 case "char" -> char.class;
637 case "byte" -> byte.class;
638
639 // Floating-point types
640 case "float" -> float.class;
641 case "double" -> double.class;
642
643 // Other types
644 case "boolean" -> boolean.class;
645 case "void" -> void.class;
646
647 default -> null;
648 };
649 }
650
651 /**
652 * Creates a new instance of the class represented by this {@code Class}
653 * object. The class is instantiated as if by a {@code new}
654 * expression with an empty argument list. The class is initialized if it
655 * has not already been initialized.
656 *
657 * @deprecated This method propagates any exception thrown by the
658 * nullary constructor, including a checked exception. Use of
659 * this method effectively bypasses the compile-time exception
660 * checking that would otherwise be performed by the compiler.
661 * The {@link
662 * java.lang.reflect.Constructor#newInstance(java.lang.Object...)
663 * Constructor.newInstance} method avoids this problem by wrapping
664 * any exception thrown by the constructor in a (checked) {@link
665 * java.lang.reflect.InvocationTargetException}.
666 *
667 * <p>The call
668 *
669 * {@snippet lang="java" :
670 * clazz.newInstance()
671 * }
672 *
673 * can be replaced by
674 *
675 * {@snippet lang="java" :
676 * clazz.getDeclaredConstructor().newInstance()
677 * }
678 *
679 * The latter sequence of calls is inferred to be able to throw
680 * the additional exception types {@link
681 * InvocationTargetException} and {@link
682 * NoSuchMethodException}. Both of these exception types are
683 * subclasses of {@link ReflectiveOperationException}.
684 *
685 * @return a newly allocated instance of the class represented by this
686 * object.
687 * @throws IllegalAccessException if the class or its nullary
688 * constructor is not accessible.
689 * @throws InstantiationException
690 * if this {@code Class} represents an abstract class,
691 * an interface, an array class, a primitive type, or void;
692 * or if the class has no nullary constructor;
693 * or if the instantiation fails for some other reason.
694 * @throws ExceptionInInitializerError if the initialization
695 * provoked by this method fails.
696 */
697 @CallerSensitive
698 @Deprecated(since="9")
699 public T newInstance()
700 throws InstantiationException, IllegalAccessException
701 {
702 // Constructor lookup
703 Constructor<T> tmpConstructor = cachedConstructor;
704 if (tmpConstructor == null) {
705 if (this == Class.class) {
706 throw new IllegalAccessException(
707 "Can not call newInstance() on the Class for java.lang.Class"
708 );
709 }
710 try {
711 Class<?>[] empty = {};
712 final Constructor<T> c = getReflectionFactory().copyConstructor(
713 getConstructor0(empty, Member.DECLARED));
714 // Disable accessibility checks on the constructor
715 // access check is done with the true caller
716 c.setAccessible(true);
717 cachedConstructor = tmpConstructor = c;
718 } catch (NoSuchMethodException e) {
719 throw (InstantiationException)
720 new InstantiationException(getName()).initCause(e);
721 }
722 }
723
724 try {
725 Class<?> caller = Reflection.getCallerClass();
726 return getReflectionFactory().newInstance(tmpConstructor, null, caller);
727 } catch (InvocationTargetException e) {
728 Unsafe.getUnsafe().throwException(e.getTargetException());
729 // Not reached
730 return null;
731 }
732 }
733
734 private transient volatile Constructor<T> cachedConstructor;
735
736 /**
737 * Determines if the specified {@code Object} is assignment-compatible
738 * with the object represented by this {@code Class}. This method is
739 * the dynamic equivalent of the Java language {@code instanceof}
740 * operator. The method returns {@code true} if the specified
741 * {@code Object} argument is non-null and can be cast to the
742 * reference type represented by this {@code Class} object without
743 * raising a {@code ClassCastException.} It returns {@code false}
744 * otherwise.
745 *
746 * <p> Specifically, if this {@code Class} object represents a
747 * declared class, this method returns {@code true} if the specified
748 * {@code Object} argument is an instance of the represented class (or
749 * of any of its subclasses); it returns {@code false} otherwise. If
750 * this {@code Class} object represents an array class, this method
751 * returns {@code true} if the specified {@code Object} argument
752 * can be converted to an object of the array class by an identity
753 * conversion or by a widening reference conversion; it returns
754 * {@code false} otherwise. If this {@code Class} object
755 * represents an interface, this method returns {@code true} if the
756 * class or any superclass of the specified {@code Object} argument
757 * implements this interface; it returns {@code false} otherwise. If
758 * this {@code Class} object represents a primitive type, this method
759 * returns {@code false}.
760 *
761 * @param obj the object to check, may be {@code null}
762 * @return true if {@code obj} is an instance of this class
763 *
764 * @since 1.1
765 */
766 @IntrinsicCandidate
767 public native boolean isInstance(Object obj);
768
769
770 /**
771 * Determines if the class or interface represented by this
772 * {@code Class} object is either the same as, or is a superclass or
773 * superinterface of, the class or interface represented by the specified
774 * {@code Class} parameter. It returns {@code true} if so;
775 * otherwise it returns {@code false}. If this {@code Class}
776 * object represents a primitive type, this method returns
777 * {@code true} if the specified {@code Class} parameter is
778 * exactly this {@code Class} object; otherwise it returns
779 * {@code false}.
780 *
781 * <p> Specifically, this method tests whether the type represented by the
782 * specified {@code Class} parameter can be converted to the type
783 * represented by this {@code Class} object via an identity conversion
784 * or via a widening reference conversion. See <cite>The Java Language
785 * Specification</cite>, sections {@jls 5.1.1} and {@jls 5.1.4},
786 * for details.
787 *
788 * @param cls the {@code Class} object to be checked
789 * @return the {@code boolean} value indicating whether objects of the
790 * type {@code cls} can be assigned to objects of this class
791 * @since 1.1
792 */
793 @IntrinsicCandidate
794 public native boolean isAssignableFrom(Class<?> cls);
795
796
797 /**
798 * Determines if this {@code Class} object represents an
799 * interface type.
800 *
801 * @return {@code true} if this {@code Class} object represents an interface;
802 * {@code false} otherwise.
803 */
804 public boolean isInterface() {
805 return Modifier.isInterface(modifiers);
806 }
807
808
809 /**
810 * Determines if this {@code Class} object represents an array class.
811 *
812 * @return {@code true} if this {@code Class} object represents an array class;
813 * {@code false} otherwise.
814 * @since 1.1
815 */
816 public boolean isArray() {
817 return componentType != null;
818 }
819
820
821 /**
822 * Determines if this {@code Class} object represents a primitive
823 * type or void.
824 *
825 * <p> There are nine predefined {@code Class} objects to
826 * represent the eight primitive types and void. These are
827 * created by the Java Virtual Machine, and have the same
828 * {@linkplain #getName() names} as the primitive types that they
829 * represent, namely {@code boolean}, {@code byte}, {@code char},
830 * {@code short}, {@code int}, {@code long}, {@code float}, and
831 * {@code double}.
832 *
833 * <p>No other class objects are considered primitive.
834 *
835 * @apiNote
836 * A {@code Class} object represented by a primitive type can be
837 * accessed via the {@code TYPE} public static final variables
838 * defined in the primitive wrapper classes such as {@link
839 * java.lang.Integer#TYPE Integer.TYPE}. In the Java programming
840 * language, the objects may be referred to by a class literal
841 * expression such as {@code int.class}. The {@code Class} object
842 * for void can be expressed as {@code void.class} or {@link
843 * java.lang.Void#TYPE Void.TYPE}.
844 *
845 * @return true if and only if this class represents a primitive type
846 *
847 * @see java.lang.Boolean#TYPE
848 * @see java.lang.Character#TYPE
849 * @see java.lang.Byte#TYPE
850 * @see java.lang.Short#TYPE
851 * @see java.lang.Integer#TYPE
852 * @see java.lang.Long#TYPE
853 * @see java.lang.Float#TYPE
854 * @see java.lang.Double#TYPE
855 * @see java.lang.Void#TYPE
856 * @since 1.1
857 * @jls 15.8.2 Class Literals
858 */
859 public boolean isPrimitive() {
860 return primitive;
861 }
862
863 /**
864 * Returns true if this {@code Class} object represents an annotation
865 * interface. Note that if this method returns true, {@link #isInterface()}
866 * would also return true, as all annotation interfaces are also interfaces.
867 *
868 * @return {@code true} if this {@code Class} object represents an annotation
869 * interface; {@code false} otherwise
870 * @since 1.5
871 */
872 public boolean isAnnotation() {
873 return (getModifiers() & ANNOTATION) != 0;
874 }
875
876 /**
877 *{@return {@code true} if and only if this class has the synthetic modifier
878 * bit set}
879 *
880 * @jls 13.1 The Form of a Binary
881 * @jvms 4.1 The {@code ClassFile} Structure
882 * @see <a
883 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
884 * programming language and JVM modeling in core reflection</a>
885 * @since 1.5
886 */
887 public boolean isSynthetic() {
888 return (getModifiers() & SYNTHETIC) != 0;
889 }
890
891 /**
892 * Returns the name of the entity (class, interface, array class,
893 * primitive type, or void) represented by this {@code Class} object.
894 *
895 * <p> If this {@code Class} object represents a class or interface,
896 * not an array class, then:
897 * <ul>
898 * <li> If the class or interface is not {@linkplain #isHidden() hidden},
899 * then the {@linkplain ClassLoader##binary-name binary name}
900 * of the class or interface is returned.
901 * <li> If the class or interface is hidden, then the result is a string
902 * of the form: {@code N + '/' + <suffix>}
903 * where {@code N} is the {@linkplain ClassLoader##binary-name binary name}
904 * indicated by the {@code class} file passed to
905 * {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
906 * Lookup::defineHiddenClass}, and {@code <suffix>} is an unqualified name.
907 * </ul>
908 *
909 * <p> If this {@code Class} object represents an array class, then
910 * the result is a string consisting of one or more '{@code [}' characters
911 * representing the depth of the array nesting, followed by the element
912 * type as encoded using the following table:
913 *
914 * <blockquote><table class="striped" id="nameFormat">
915 * <caption style="display:none">Element types and encodings</caption>
916 * <thead>
917 * <tr><th scope="col"> Element Type <th scope="col"> Encoding
918 * </thead>
919 * <tbody style="text-align:left">
920 * <tr><th scope="row"> {@code boolean} <td style="text-align:center"> {@code Z}
921 * <tr><th scope="row"> {@code byte} <td style="text-align:center"> {@code B}
922 * <tr><th scope="row"> {@code char} <td style="text-align:center"> {@code C}
923 * <tr><th scope="row"> class or interface with {@linkplain ClassLoader##binary-name binary name} <i>N</i>
924 * <td style="text-align:center"> {@code L}<em>N</em>{@code ;}
925 * <tr><th scope="row"> {@code double} <td style="text-align:center"> {@code D}
926 * <tr><th scope="row"> {@code float} <td style="text-align:center"> {@code F}
927 * <tr><th scope="row"> {@code int} <td style="text-align:center"> {@code I}
928 * <tr><th scope="row"> {@code long} <td style="text-align:center"> {@code J}
929 * <tr><th scope="row"> {@code short} <td style="text-align:center"> {@code S}
930 * </tbody>
931 * </table></blockquote>
932 *
933 * <p> If this {@code Class} object represents a primitive type or {@code void},
934 * then the result is a string with the same spelling as the Java language
935 * keyword which corresponds to the primitive type or {@code void}.
936 *
937 * <p> Examples:
938 * <blockquote><pre>
939 * String.class.getName()
940 * returns "java.lang.String"
941 * Character.UnicodeBlock.class.getName()
942 * returns "java.lang.Character$UnicodeBlock"
943 * byte.class.getName()
944 * returns "byte"
945 * (new Object[3]).getClass().getName()
946 * returns "[Ljava.lang.Object;"
947 * (new int[3][4][5][6][7][8][9]).getClass().getName()
948 * returns "[[[[[[[I"
949 * </pre></blockquote>
950 *
951 * @apiNote
952 * Distinct class objects can have the same name but different class loaders.
953 *
954 * @return the name of the class, interface, or other entity
955 * represented by this {@code Class} object.
956 * @jls 13.1 The Form of a Binary
957 */
958 public String getName() {
959 String name = this.name;
960 return name != null ? name : initClassName();
961 }
962
963 // Cache the name to reduce the number of calls into the VM.
964 // This field would be set by VM itself during initClassName call.
965 private transient String name;
966 private native String initClassName();
967
968 /**
969 * Returns the class loader for the class. Some implementations may use
970 * null to represent the bootstrap class loader. This method will return
971 * null in such implementations if this class was loaded by the bootstrap
972 * class loader.
973 *
974 * <p>If this {@code Class} object
975 * represents a primitive type or void, null is returned.
976 *
977 * @return the class loader that loaded the class or interface
978 * represented by this {@code Class} object.
979 * @see java.lang.ClassLoader
980 */
981 public ClassLoader getClassLoader() {
982 return classLoader;
983 }
984
985 // Package-private to allow ClassLoader access
986 ClassLoader getClassLoader0() { return classLoader; }
987
988 /**
989 * Returns the module that this class or interface is a member of.
990 *
991 * If this class represents an array type then this method returns the
992 * {@code Module} for the element type. If this class represents a
993 * primitive type or void, then the {@code Module} object for the
994 * {@code java.base} module is returned.
995 *
996 * If this class is in an unnamed module then the {@linkplain
997 * ClassLoader#getUnnamedModule() unnamed} {@code Module} of the class
998 * loader for this class is returned.
999 *
1000 * @return the module that this class or interface is a member of
1001 *
1002 * @since 9
1003 */
1004 public Module getModule() {
1005 return module;
1006 }
1007
1008 // set by VM
1009 @Stable
1010 private transient Module module;
1011
1012 // Initialized in JVM not by private constructor
1013 // This field is filtered from reflection access, i.e. getDeclaredField
1014 // will throw NoSuchFieldException
1015 private final ClassLoader classLoader;
1016
1017 private transient Object classData; // Set by VM
1018 private transient Object[] signers; // Read by VM, mutable
1019 private final transient char modifiers; // Set by the VM
1020 private final transient char classFileAccessFlags; // Set by the VM
1021 private final transient boolean primitive; // Set by the VM if the Class is a primitive type.
1022
1023 // package-private
1024 Object getClassData() {
1025 return classData;
1026 }
1027
1028 /**
1029 * Returns an array of {@code TypeVariable} objects that represent the
1030 * type variables declared by the generic declaration represented by this
1031 * {@code GenericDeclaration} object, in declaration order. Returns an
1032 * array of length 0 if the underlying generic declaration declares no type
1033 * variables.
1034 *
1035 * @return an array of {@code TypeVariable} objects that represent
1036 * the type variables declared by this generic declaration
1037 * @throws java.lang.reflect.GenericSignatureFormatError if the generic
1038 * signature of this generic declaration does not conform to
1039 * the format specified in section {@jvms 4.7.9} of
1040 * <cite>The Java Virtual Machine Specification</cite>
1041 * @since 1.5
1042 */
1043 @SuppressWarnings("unchecked")
1044 public TypeVariable<Class<T>>[] getTypeParameters() {
1045 ClassRepository info = getGenericInfo();
1046 if (info != null)
1047 return (TypeVariable<Class<T>>[])info.getTypeParameters();
1048 else
1049 return (TypeVariable<Class<T>>[])new TypeVariable<?>[0];
1050 }
1051
1052
1053 /**
1054 * Returns the {@code Class} representing the direct superclass of the
1055 * entity (class, interface, primitive type or void) represented by
1056 * this {@code Class}. If this {@code Class} represents either the
1057 * {@code Object} class, an interface, a primitive type, or void, then
1058 * null is returned. If this {@code Class} object represents an array class
1059 * then the {@code Class} object representing the {@code Object} class is
1060 * returned.
1061 *
1062 * @return the direct superclass of the class represented by this {@code Class} object
1063 */
1064 @IntrinsicCandidate
1065 public native Class<? super T> getSuperclass();
1066
1067
1068 /**
1069 * Returns the {@code Type} representing the direct superclass of
1070 * the entity (class, interface, primitive type or void) represented by
1071 * this {@code Class} object.
1072 *
1073 * <p>If the superclass is a parameterized type, the {@code Type}
1074 * object returned must accurately reflect the actual type
1075 * arguments used in the source code. The parameterized type
1076 * representing the superclass is created if it had not been
1077 * created before. See the declaration of {@link
1078 * java.lang.reflect.ParameterizedType ParameterizedType} for the
1079 * semantics of the creation process for parameterized types. If
1080 * this {@code Class} object represents either the {@code Object}
1081 * class, an interface, a primitive type, or void, then null is
1082 * returned. If this {@code Class} object represents an array class
1083 * then the {@code Class} object representing the {@code Object} class is
1084 * returned.
1085 *
1086 * @throws java.lang.reflect.GenericSignatureFormatError if the generic
1087 * class signature does not conform to the format specified in
1088 * section {@jvms 4.7.9} of <cite>The Java Virtual
1089 * Machine Specification</cite>
1090 * @throws TypeNotPresentException if the generic superclass
1091 * refers to a non-existent type declaration
1092 * @throws java.lang.reflect.MalformedParameterizedTypeException if the
1093 * generic superclass refers to a parameterized type that cannot be
1094 * instantiated for any reason
1095 * @return the direct superclass of the class represented by this {@code Class} object
1096 * @since 1.5
1097 */
1098 public Type getGenericSuperclass() {
1099 ClassRepository info = getGenericInfo();
1100 if (info == null) {
1101 return getSuperclass();
1102 }
1103
1104 // Historical irregularity:
1105 // Generic signature marks interfaces with superclass = Object
1106 // but this API returns null for interfaces
1107 if (isInterface()) {
1108 return null;
1109 }
1110
1111 return info.getSuperclass();
1112 }
1113
1114 /**
1115 * Gets the package of this class.
1116 *
1117 * <p>If this class represents an array type, a primitive type or void,
1118 * this method returns {@code null}.
1119 *
1120 * @return the package of this class.
1121 */
1122 public Package getPackage() {
1123 if (isPrimitive() || isArray()) {
1124 return null;
1125 }
1126 ClassLoader cl = classLoader;
1127 return cl != null ? cl.definePackage(this)
1128 : BootLoader.definePackage(this);
1129 }
1130
1131 /**
1132 * Returns the fully qualified package name.
1133 *
1134 * <p> If this class is a top level class, then this method returns the fully
1135 * qualified name of the package that the class is a member of, or the
1136 * empty string if the class is in an unnamed package.
1137 *
1138 * <p> If this class is a member class, then this method is equivalent to
1139 * invoking {@code getPackageName()} on the {@linkplain #getEnclosingClass
1140 * enclosing class}.
1141 *
1142 * <p> If this class is a {@linkplain #isLocalClass local class} or an {@linkplain
1143 * #isAnonymousClass() anonymous class}, then this method is equivalent to
1144 * invoking {@code getPackageName()} on the {@linkplain #getDeclaringClass
1145 * declaring class} of the {@linkplain #getEnclosingMethod enclosing method} or
1146 * {@linkplain #getEnclosingConstructor enclosing constructor}.
1147 *
1148 * <p> If this class represents an array type then this method returns the
1149 * package name of the element type. If this class represents a primitive
1150 * type or void then the package name "{@code java.lang}" is returned.
1151 *
1152 * @return the fully qualified package name
1153 *
1154 * @since 9
1155 * @jls 6.7 Fully Qualified Names and Canonical Names
1156 */
1157 public String getPackageName() {
1158 String pn = this.packageName;
1159 if (pn == null) {
1160 Class<?> c = isArray() ? elementType() : this;
1161 if (c.isPrimitive()) {
1162 pn = "java.lang";
1163 } else {
1164 String cn = c.getName();
1165 int dot = cn.lastIndexOf('.');
1166 pn = (dot != -1) ? cn.substring(0, dot).intern() : "";
1167 }
1168 this.packageName = pn;
1169 }
1170 return pn;
1171 }
1172
1173 // cached package name
1174 private transient String packageName;
1175
1176 /**
1177 * Returns the interfaces directly implemented by the class or interface
1178 * represented by this {@code Class} object.
1179 *
1180 * <p>If this {@code Class} object represents a class, the return value is an array
1181 * containing objects representing all interfaces directly implemented by
1182 * the class. The order of the interface objects in the array corresponds
1183 * to the order of the interface names in the {@code implements} clause of
1184 * the declaration of the class represented by this {@code Class} object. For example,
1185 * given the declaration:
1186 * <blockquote>
1187 * {@code class Shimmer implements FloorWax, DessertTopping { ... }}
1188 * </blockquote>
1189 * suppose the value of {@code s} is an instance of
1190 * {@code Shimmer}; the value of the expression:
1191 * <blockquote>
1192 * {@code s.getClass().getInterfaces()[0]}
1193 * </blockquote>
1194 * is the {@code Class} object that represents interface
1195 * {@code FloorWax}; and the value of:
1196 * <blockquote>
1197 * {@code s.getClass().getInterfaces()[1]}
1198 * </blockquote>
1199 * is the {@code Class} object that represents interface
1200 * {@code DessertTopping}.
1201 *
1202 * <p>If this {@code Class} object represents an interface, the array contains objects
1203 * representing all interfaces directly extended by the interface. The
1204 * order of the interface objects in the array corresponds to the order of
1205 * the interface names in the {@code extends} clause of the declaration of
1206 * the interface represented by this {@code Class} object.
1207 *
1208 * <p>If this {@code Class} object represents a class or interface that implements no
1209 * interfaces, the method returns an array of length 0.
1210 *
1211 * <p>If this {@code Class} object represents a primitive type or void, the method
1212 * returns an array of length 0.
1213 *
1214 * <p>If this {@code Class} object represents an array type, the
1215 * interfaces {@code Cloneable} and {@code java.io.Serializable} are
1216 * returned in that order.
1217 *
1218 * @return an array of interfaces directly implemented by this class
1219 */
1220 public Class<?>[] getInterfaces() {
1221 // defensively copy before handing over to user code
1222 return getInterfaces(true);
1223 }
1224
1225 private Class<?>[] getInterfaces(boolean cloneArray) {
1226 ReflectionData<T> rd = reflectionData();
1227 Class<?>[] interfaces = rd.interfaces;
1228 if (interfaces == null) {
1229 interfaces = getInterfaces0();
1230 rd.interfaces = interfaces;
1231 }
1232 // defensively copy if requested
1233 return cloneArray ? interfaces.clone() : interfaces;
1234 }
1235
1236 private native Class<?>[] getInterfaces0();
1237
1238 /**
1239 * Returns the {@code Type}s representing the interfaces
1240 * directly implemented by the class or interface represented by
1241 * this {@code Class} object.
1242 *
1243 * <p>If a superinterface is a parameterized type, the
1244 * {@code Type} object returned for it must accurately reflect
1245 * the actual type arguments used in the source code. The
1246 * parameterized type representing each superinterface is created
1247 * if it had not been created before. See the declaration of
1248 * {@link java.lang.reflect.ParameterizedType ParameterizedType}
1249 * for the semantics of the creation process for parameterized
1250 * types.
1251 *
1252 * <p>If this {@code Class} object represents a class, the return value is an array
1253 * containing objects representing all interfaces directly implemented by
1254 * the class. The order of the interface objects in the array corresponds
1255 * to the order of the interface names in the {@code implements} clause of
1256 * the declaration of the class represented by this {@code Class} object.
1257 *
1258 * <p>If this {@code Class} object represents an interface, the array contains objects
1259 * representing all interfaces directly extended by the interface. The
1260 * order of the interface objects in the array corresponds to the order of
1261 * the interface names in the {@code extends} clause of the declaration of
1262 * the interface represented by this {@code Class} object.
1263 *
1264 * <p>If this {@code Class} object represents a class or interface that implements no
1265 * interfaces, the method returns an array of length 0.
1266 *
1267 * <p>If this {@code Class} object represents a primitive type or void, the method
1268 * returns an array of length 0.
1269 *
1270 * <p>If this {@code Class} object represents an array type, the
1271 * interfaces {@code Cloneable} and {@code java.io.Serializable} are
1272 * returned in that order.
1273 *
1274 * @throws java.lang.reflect.GenericSignatureFormatError
1275 * if the generic class signature does not conform to the
1276 * format specified in section {@jvms 4.7.9} of <cite>The
1277 * Java Virtual Machine Specification</cite>
1278 * @throws TypeNotPresentException if any of the generic
1279 * superinterfaces refers to a non-existent type declaration
1280 * @throws java.lang.reflect.MalformedParameterizedTypeException
1281 * if any of the generic superinterfaces refer to a parameterized
1282 * type that cannot be instantiated for any reason
1283 * @return an array of interfaces directly implemented by this class
1284 * @since 1.5
1285 */
1286 public Type[] getGenericInterfaces() {
1287 ClassRepository info = getGenericInfo();
1288 return (info == null) ? getInterfaces() : info.getSuperInterfaces();
1289 }
1290
1291
1292 /**
1293 * Returns the {@code Class} representing the component type of an
1294 * array. If this class does not represent an array class this method
1295 * returns null.
1296 *
1297 * @return the {@code Class} representing the component type of this
1298 * class if this class is an array
1299 * @see java.lang.reflect.Array
1300 * @since 1.1
1301 */
1302 public Class<?> getComponentType() {
1303 return componentType;
1304 }
1305
1306 // The componentType field's null value is the sole indication that the class
1307 // is an array - see isArray().
1308 private transient final Class<?> componentType;
1309
1310 /*
1311 * Returns the {@code Class} representing the element type of an array class.
1312 * If this class does not represent an array class, then this method returns
1313 * {@code null}.
1314 */
1315 private Class<?> elementType() {
1316 if (!isArray()) return null;
1317
1318 Class<?> c = this;
1319 while (c.isArray()) {
1320 c = c.getComponentType();
1321 }
1322 return c;
1323 }
1324
1325 /**
1326 * Returns the Java language modifiers for this class or interface, encoded
1327 * in an integer. The modifiers consist of the Java Virtual Machine's
1328 * constants for {@code public}, {@code protected},
1329 * {@code private}, {@code final}, {@code static},
1330 * {@code abstract} and {@code interface}; they should be decoded
1331 * using the methods of class {@code Modifier}.
1332 *
1333 * <p> If the underlying class is an array class:
1334 * <ul>
1335 * <li> its {@code public}, {@code private} and {@code protected}
1336 * modifiers are the same as those of its component type
1337 * <li> its {@code abstract} and {@code final} modifiers are always
1338 * {@code true}
1339 * <li> its interface modifier is always {@code false}, even when
1340 * the component type is an interface
1341 * </ul>
1342 * If this {@code Class} object represents a primitive type or
1343 * void, its {@code public}, {@code abstract}, and {@code final}
1344 * modifiers are always {@code true}.
1345 * For {@code Class} objects representing void, primitive types, and
1346 * arrays, the values of other modifiers are {@code false} other
1347 * than as specified above.
1348 *
1349 * <p> The modifier encodings are defined in section {@jvms 4.1}
1350 * of <cite>The Java Virtual Machine Specification</cite>.
1351 *
1352 * @return the {@code int} representing the modifiers for this class
1353 * @see java.lang.reflect.Modifier
1354 * @see #accessFlags()
1355 * @see <a
1356 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
1357 * programming language and JVM modeling in core reflection</a>
1358 * @since 1.1
1359 * @jls 8.1.1 Class Modifiers
1360 * @jls 9.1.1 Interface Modifiers
1361 * @jvms 4.1 The {@code ClassFile} Structure
1362 */
1363 public int getModifiers() { return modifiers; }
1364
1365 /**
1366 * {@return an unmodifiable set of the {@linkplain AccessFlag access
1367 * flags} for this class, possibly empty}
1368 *
1369 * <p> If the underlying class is an array class:
1370 * <ul>
1371 * <li> its {@code PUBLIC}, {@code PRIVATE} and {@code PROTECTED}
1372 * access flags are the same as those of its component type
1373 * <li> its {@code ABSTRACT} and {@code FINAL} flags are present
1374 * <li> its {@code INTERFACE} flag is absent, even when the
1375 * component type is an interface
1376 * </ul>
1377 * If this {@code Class} object represents a primitive type or
1378 * void, the flags are {@code PUBLIC}, {@code ABSTRACT}, and
1379 * {@code FINAL}.
1380 * For {@code Class} objects representing void, primitive types, and
1381 * arrays, access flags are absent other than as specified above.
1382 *
1383 * @see #getModifiers()
1384 * @jvms 4.1 The ClassFile Structure
1385 * @jvms 4.7.6 The InnerClasses Attribute
1386 * @since 20
1387 */
1388 public Set<AccessFlag> accessFlags() {
1389 // Location.CLASS allows SUPER and AccessFlag.MODULE which
1390 // INNER_CLASS forbids. INNER_CLASS allows PRIVATE, PROTECTED,
1391 // and STATIC, which are not allowed on Location.CLASS.
1392 // Use getClassFileAccessFlags to expose SUPER status.
1393 var location = (isMemberClass() || isLocalClass() ||
1394 isAnonymousClass() || isArray()) ?
1395 AccessFlag.Location.INNER_CLASS :
1396 AccessFlag.Location.CLASS;
1397 return getReflectionFactory().parseAccessFlags((location == AccessFlag.Location.CLASS) ?
1398 getClassFileAccessFlags() : getModifiers(), location, this);
1399 }
1400
1401 /**
1402 * Gets the signers of this class.
1403 *
1404 * @return the signers of this class, or null if there are no signers. In
1405 * particular, this method returns null if this {@code Class} object represents
1406 * a primitive type or void.
1407 * @since 1.1
1408 */
1409 public Object[] getSigners() {
1410 var signers = this.signers;
1411 return signers == null ? null : signers.clone();
1412 }
1413
1414 /**
1415 * Set the signers of this class.
1416 */
1417 void setSigners(Object[] signers) {
1418 if (!isPrimitive() && !isArray()) {
1419 this.signers = signers;
1420 }
1421 }
1422
1423 /**
1424 * If this {@code Class} object represents a local or anonymous
1425 * class within a method, returns a {@link
1426 * java.lang.reflect.Method Method} object representing the
1427 * immediately enclosing method of the underlying class. Returns
1428 * {@code null} otherwise.
1429 *
1430 * In particular, this method returns {@code null} if the underlying
1431 * class is a local or anonymous class immediately enclosed by a class or
1432 * interface declaration, instance initializer or static initializer.
1433 *
1434 * @return the immediately enclosing method of the underlying class, if
1435 * that class is a local or anonymous class; otherwise {@code null}.
1436 *
1437 * @since 1.5
1438 */
1439 public Method getEnclosingMethod() {
1440 EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
1441
1442 if (enclosingInfo == null)
1443 return null;
1444 else {
1445 if (!enclosingInfo.isMethod())
1446 return null;
1447
1448 List<Class<?>> types = BytecodeDescriptor.parseMethod(enclosingInfo.getDescriptor(), getClassLoader());
1449 Class<?> returnType = types.removeLast();
1450 Class<?>[] parameterClasses = types.toArray(EMPTY_CLASS_ARRAY);
1451
1452 final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
1453 Method[] candidates = enclosingCandidate.privateGetDeclaredMethods(false);
1454
1455 /*
1456 * Loop over all declared methods; match method name,
1457 * number of and type of parameters, *and* return
1458 * type. Matching return type is also necessary
1459 * because of covariant returns, etc.
1460 */
1461 ReflectionFactory fact = getReflectionFactory();
1462 for (Method m : candidates) {
1463 if (m.getName().equals(enclosingInfo.getName()) &&
1464 arrayContentsEq(parameterClasses,
1465 fact.getExecutableSharedParameterTypes(m))) {
1466 // finally, check return type
1467 if (m.getReturnType().equals(returnType)) {
1468 return fact.copyMethod(m);
1469 }
1470 }
1471 }
1472
1473 throw new InternalError("Enclosing method not found");
1474 }
1475 }
1476
1477 private native Object[] getEnclosingMethod0();
1478
1479 private EnclosingMethodInfo getEnclosingMethodInfo() {
1480 Object[] enclosingInfo = getEnclosingMethod0();
1481 if (enclosingInfo == null)
1482 return null;
1483 else {
1484 return new EnclosingMethodInfo(enclosingInfo);
1485 }
1486 }
1487
1488 private static final class EnclosingMethodInfo {
1489 private final Class<?> enclosingClass;
1490 private final String name;
1491 private final String descriptor;
1492
1493 static void validate(Object[] enclosingInfo) {
1494 if (enclosingInfo.length != 3)
1495 throw new InternalError("Malformed enclosing method information");
1496 try {
1497 // The array is expected to have three elements:
1498
1499 // the immediately enclosing class
1500 Class<?> enclosingClass = (Class<?>)enclosingInfo[0];
1501 assert(enclosingClass != null);
1502
1503 // the immediately enclosing method or constructor's
1504 // name (can be null).
1505 String name = (String)enclosingInfo[1];
1506
1507 // the immediately enclosing method or constructor's
1508 // descriptor (null iff name is).
1509 String descriptor = (String)enclosingInfo[2];
1510 assert((name != null && descriptor != null) || name == descriptor);
1511 } catch (ClassCastException cce) {
1512 throw new InternalError("Invalid type in enclosing method information", cce);
1513 }
1514 }
1515
1516 EnclosingMethodInfo(Object[] enclosingInfo) {
1517 validate(enclosingInfo);
1518 this.enclosingClass = (Class<?>)enclosingInfo[0];
1519 this.name = (String)enclosingInfo[1];
1520 this.descriptor = (String)enclosingInfo[2];
1521 }
1522
1523 boolean isPartial() {
1524 return enclosingClass == null || name == null || descriptor == null;
1525 }
1526
1527 boolean isConstructor() { return !isPartial() && ConstantDescs.INIT_NAME.equals(name); }
1528
1529 boolean isMethod() { return !isPartial() && !isConstructor() && !ConstantDescs.CLASS_INIT_NAME.equals(name); }
1530
1531 Class<?> getEnclosingClass() { return enclosingClass; }
1532
1533 String getName() { return name; }
1534
1535 String getDescriptor() {
1536 // hotspot validates this descriptor to be either a field or method
1537 // descriptor as the "type" in a NameAndType in verification.
1538 // So this can still be a field descriptor
1539 if (descriptor.isEmpty() || descriptor.charAt(0) != '(') {
1540 throw new GenericSignatureFormatError("Bad method signature: " + descriptor);
1541 }
1542 return descriptor;
1543 }
1544 }
1545
1546 private static Class<?> toClass(Type o) {
1547 if (o instanceof GenericArrayType gat)
1548 return toClass(gat.getGenericComponentType()).arrayType();
1549 return (Class<?>)o;
1550 }
1551
1552 /**
1553 * If this {@code Class} object represents a local or anonymous
1554 * class within a constructor, returns a {@link
1555 * java.lang.reflect.Constructor Constructor} object representing
1556 * the immediately enclosing constructor of the underlying
1557 * class. Returns {@code null} otherwise. In particular, this
1558 * method returns {@code null} if the underlying class is a local
1559 * or anonymous class immediately enclosed by a class or
1560 * interface declaration, instance initializer or static initializer.
1561 *
1562 * @return the immediately enclosing constructor of the underlying class, if
1563 * that class is a local or anonymous class; otherwise {@code null}.
1564 *
1565 * @since 1.5
1566 */
1567 public Constructor<?> getEnclosingConstructor() {
1568 EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
1569
1570 if (enclosingInfo == null)
1571 return null;
1572 else {
1573 if (!enclosingInfo.isConstructor())
1574 return null;
1575
1576 List<Class<?>> types = BytecodeDescriptor.parseMethod(enclosingInfo.getDescriptor(), getClassLoader());
1577 types.removeLast();
1578 Class<?>[] parameterClasses = types.toArray(EMPTY_CLASS_ARRAY);
1579
1580 final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
1581 Constructor<?>[] candidates = enclosingCandidate
1582 .privateGetDeclaredConstructors(false);
1583 /*
1584 * Loop over all declared constructors; match number
1585 * of and type of parameters.
1586 */
1587 ReflectionFactory fact = getReflectionFactory();
1588 for (Constructor<?> c : candidates) {
1589 if (arrayContentsEq(parameterClasses,
1590 fact.getExecutableSharedParameterTypes(c))) {
1591 return fact.copyConstructor(c);
1592 }
1593 }
1594
1595 throw new InternalError("Enclosing constructor not found");
1596 }
1597 }
1598
1599
1600 /**
1601 * If the class or interface represented by this {@code Class} object
1602 * is a member of another class, returns the {@code Class} object
1603 * representing the class in which it was declared. This method returns
1604 * null if this class or interface is not a member of any other class. If
1605 * this {@code Class} object represents an array class, a primitive
1606 * type, or void, then this method returns null.
1607 *
1608 * @return the declaring class for this class
1609 * @since 1.1
1610 */
1611 public Class<?> getDeclaringClass() {
1612 return getDeclaringClass0();
1613 }
1614
1615 private native Class<?> getDeclaringClass0();
1616
1617
1618 /**
1619 * Returns the immediately enclosing class of the underlying
1620 * class. If the underlying class is a top level class this
1621 * method returns {@code null}.
1622 * @return the immediately enclosing class of the underlying class
1623 * @since 1.5
1624 */
1625 public Class<?> getEnclosingClass() {
1626 // There are five kinds of classes (or interfaces):
1627 // a) Top level classes
1628 // b) Nested classes (static member classes)
1629 // c) Inner classes (non-static member classes)
1630 // d) Local classes (named classes declared within a method)
1631 // e) Anonymous classes
1632
1633
1634 // JVM Spec 4.7.7: A class must have an EnclosingMethod
1635 // attribute if and only if it is a local class or an
1636 // anonymous class.
1637 EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
1638 Class<?> enclosingCandidate;
1639
1640 if (enclosingInfo == null) {
1641 // This is a top level or a nested class or an inner class (a, b, or c)
1642 enclosingCandidate = getDeclaringClass0();
1643 } else {
1644 Class<?> enclosingClass = enclosingInfo.getEnclosingClass();
1645 // This is a local class or an anonymous class (d or e)
1646 if (enclosingClass == this || enclosingClass == null)
1647 throw new InternalError("Malformed enclosing method information");
1648 else
1649 enclosingCandidate = enclosingClass;
1650 }
1651 return enclosingCandidate;
1652 }
1653
1654 /**
1655 * Returns the simple name of the underlying class as given in the
1656 * source code. An empty string is returned if the underlying class is
1657 * {@linkplain #isAnonymousClass() anonymous}.
1658 * A {@linkplain #isSynthetic() synthetic class}, one not present
1659 * in source code, can have a non-empty name including special
1660 * characters, such as "{@code $}".
1661 *
1662 * <p>The simple name of an {@linkplain #isArray() array class} is the simple name of the
1663 * component type with "[]" appended. In particular the simple
1664 * name of an array class whose component type is anonymous is "[]".
1665 *
1666 * @return the simple name of the underlying class
1667 * @since 1.5
1668 */
1669 public String getSimpleName() {
1670 ReflectionData<T> rd = reflectionData();
1671 String simpleName = rd.simpleName;
1672 if (simpleName == null) {
1673 rd.simpleName = simpleName = getSimpleName0();
1674 }
1675 return simpleName;
1676 }
1677
1678 private String getSimpleName0() {
1679 if (isArray()) {
1680 return getComponentType().getSimpleName().concat("[]");
1681 }
1682 String simpleName = getSimpleBinaryName();
1683 if (simpleName == null) { // top level class
1684 simpleName = getName();
1685 simpleName = simpleName.substring(simpleName.lastIndexOf('.') + 1); // strip the package name
1686 }
1687 return simpleName;
1688 }
1689
1690 /**
1691 * Return an informative string for the name of this class or interface.
1692 *
1693 * @return an informative string for the name of this class or interface
1694 * @since 1.8
1695 */
1696 public String getTypeName() {
1697 if (isArray()) {
1698 try {
1699 Class<?> cl = this;
1700 int dimensions = 0;
1701 do {
1702 dimensions++;
1703 cl = cl.getComponentType();
1704 } while (cl.isArray());
1705 return cl.getName().concat("[]".repeat(dimensions));
1706 } catch (Throwable e) { /*FALLTHRU*/ }
1707 }
1708 return getName();
1709 }
1710
1711 /**
1712 * Returns the canonical name of the underlying class as
1713 * defined by <cite>The Java Language Specification</cite>.
1714 * Returns {@code null} if the underlying class does not have a canonical
1715 * name. Classes without canonical names include:
1716 * <ul>
1717 * <li>a {@linkplain #isLocalClass() local class}
1718 * <li>a {@linkplain #isAnonymousClass() anonymous class}
1719 * <li>a {@linkplain #isHidden() hidden class}
1720 * <li>an array whose component type does not have a canonical name</li>
1721 * </ul>
1722 *
1723 * The canonical name for a primitive class is the keyword for the
1724 * corresponding primitive type ({@code byte}, {@code short},
1725 * {@code char}, {@code int}, and so on).
1726 *
1727 * <p>An array type has a canonical name if and only if its
1728 * component type has a canonical name. When an array type has a
1729 * canonical name, it is equal to the canonical name of the
1730 * component type followed by "{@code []}".
1731 *
1732 * @return the canonical name of the underlying class if it exists, and
1733 * {@code null} otherwise.
1734 * @jls 6.7 Fully Qualified Names and Canonical Names
1735 * @since 1.5
1736 */
1737 public String getCanonicalName() {
1738 ReflectionData<T> rd = reflectionData();
1739 String canonicalName = rd.canonicalName;
1740 if (canonicalName == null) {
1741 rd.canonicalName = canonicalName = getCanonicalName0();
1742 }
1743 return canonicalName == ReflectionData.NULL_SENTINEL? null : canonicalName;
1744 }
1745
1746 private String getCanonicalName0() {
1747 if (isArray()) {
1748 String canonicalName = getComponentType().getCanonicalName();
1749 if (canonicalName != null)
1750 return canonicalName.concat("[]");
1751 else
1752 return ReflectionData.NULL_SENTINEL;
1753 }
1754 if (isHidden() || isLocalOrAnonymousClass())
1755 return ReflectionData.NULL_SENTINEL;
1756 Class<?> enclosingClass = getEnclosingClass();
1757 if (enclosingClass == null) { // top level class
1758 return getName();
1759 } else {
1760 String enclosingName = enclosingClass.getCanonicalName();
1761 if (enclosingName == null)
1762 return ReflectionData.NULL_SENTINEL;
1763 String simpleName = getSimpleName();
1764 return new StringBuilder(enclosingName.length() + simpleName.length() + 1)
1765 .append(enclosingName)
1766 .append('.')
1767 .append(simpleName)
1768 .toString();
1769 }
1770 }
1771
1772 /**
1773 * Returns {@code true} if and only if the underlying class
1774 * is an anonymous class.
1775 *
1776 * @apiNote
1777 * An anonymous class is not a {@linkplain #isHidden() hidden class}.
1778 *
1779 * @return {@code true} if and only if this class is an anonymous class.
1780 * @since 1.5
1781 * @jls 15.9.5 Anonymous Class Declarations
1782 */
1783 public boolean isAnonymousClass() {
1784 return !isArray() && isLocalOrAnonymousClass() &&
1785 getSimpleBinaryName0() == null;
1786 }
1787
1788 /**
1789 * Returns {@code true} if and only if the underlying class
1790 * is a local class.
1791 *
1792 * @return {@code true} if and only if this class is a local class.
1793 * @since 1.5
1794 * @jls 14.3 Local Class and Interface Declarations
1795 */
1796 public boolean isLocalClass() {
1797 return isLocalOrAnonymousClass() &&
1798 (isArray() || getSimpleBinaryName0() != null);
1799 }
1800
1801 /**
1802 * Returns {@code true} if and only if the underlying class
1803 * is a member class.
1804 *
1805 * @return {@code true} if and only if this class is a member class.
1806 * @since 1.5
1807 * @jls 8.5 Member Class and Interface Declarations
1808 */
1809 public boolean isMemberClass() {
1810 return !isLocalOrAnonymousClass() && getDeclaringClass0() != null;
1811 }
1812
1813 /**
1814 * Returns the "simple binary name" of the underlying class, i.e.,
1815 * the binary name without the leading enclosing class name.
1816 * Returns {@code null} if the underlying class is a top level
1817 * class.
1818 */
1819 private String getSimpleBinaryName() {
1820 if (isTopLevelClass())
1821 return null;
1822 String name = getSimpleBinaryName0();
1823 if (name == null) // anonymous class
1824 return "";
1825 return name;
1826 }
1827
1828 private native String getSimpleBinaryName0();
1829
1830 /**
1831 * Returns {@code true} if this is a top level class. Returns {@code false}
1832 * otherwise.
1833 */
1834 private boolean isTopLevelClass() {
1835 return !isLocalOrAnonymousClass() && getDeclaringClass0() == null;
1836 }
1837
1838 /**
1839 * Returns {@code true} if this is a local class or an anonymous
1840 * class. Returns {@code false} otherwise.
1841 */
1842 private boolean isLocalOrAnonymousClass() {
1843 // JVM Spec 4.7.7: A class must have an EnclosingMethod
1844 // attribute if and only if it is a local class or an
1845 // anonymous class.
1846 return hasEnclosingMethodInfo();
1847 }
1848
1849 private boolean hasEnclosingMethodInfo() {
1850 Object[] enclosingInfo = getEnclosingMethod0();
1851 if (enclosingInfo != null) {
1852 EnclosingMethodInfo.validate(enclosingInfo);
1853 return true;
1854 }
1855 return false;
1856 }
1857
1858 /**
1859 * Returns an array containing {@code Class} objects representing all
1860 * the public classes and interfaces that are members of the class
1861 * represented by this {@code Class} object. This includes public
1862 * class and interface members inherited from superclasses and public class
1863 * and interface members declared by the class. This method returns an
1864 * array of length 0 if this {@code Class} object has no public member
1865 * classes or interfaces. This method also returns an array of length 0 if
1866 * this {@code Class} object represents a primitive type, an array
1867 * class, or void.
1868 *
1869 * @return the array of {@code Class} objects representing the public
1870 * members of this class
1871 * @since 1.1
1872 */
1873 public Class<?>[] getClasses() {
1874 List<Class<?>> list = new ArrayList<>();
1875 Class<?> currentClass = Class.this;
1876 while (currentClass != null) {
1877 for (Class<?> m : currentClass.getDeclaredClasses()) {
1878 if (Modifier.isPublic(m.getModifiers())) {
1879 list.add(m);
1880 }
1881 }
1882 currentClass = currentClass.getSuperclass();
1883 }
1884 return list.toArray(EMPTY_CLASS_ARRAY);
1885 }
1886
1887
1888 /**
1889 * Returns an array containing {@code Field} objects reflecting all
1890 * the accessible public fields of the class or interface represented by
1891 * this {@code Class} object.
1892 *
1893 * <p> If this {@code Class} object represents a class or interface with
1894 * no accessible public fields, then this method returns an array of length
1895 * 0.
1896 *
1897 * <p> If this {@code Class} object represents a class, then this method
1898 * returns the public fields of the class and of all its superclasses and
1899 * superinterfaces.
1900 *
1901 * <p> If this {@code Class} object represents an interface, then this
1902 * method returns the fields of the interface and of all its
1903 * superinterfaces.
1904 *
1905 * <p> If this {@code Class} object represents an array type, a primitive
1906 * type, or void, then this method returns an array of length 0.
1907 *
1908 * <p> The elements in the returned array are not sorted and are not in any
1909 * particular order.
1910 *
1911 * @return the array of {@code Field} objects representing the
1912 * public fields
1913 *
1914 * @since 1.1
1915 * @jls 8.2 Class Members
1916 * @jls 8.3 Field Declarations
1917 */
1918 public Field[] getFields() {
1919 return copyFields(privateGetPublicFields());
1920 }
1921
1922
1923 /**
1924 * Returns an array containing {@code Method} objects reflecting all the
1925 * public methods of the class or interface represented by this {@code
1926 * Class} object, including those declared by the class or interface and
1927 * those inherited from superclasses and superinterfaces.
1928 *
1929 * <p> If this {@code Class} object represents an array type, then the
1930 * returned array has a {@code Method} object for each of the public
1931 * methods inherited by the array type from {@code Object}. It does not
1932 * contain a {@code Method} object for {@code clone()}.
1933 *
1934 * <p> If this {@code Class} object represents an interface then the
1935 * returned array does not contain any implicitly declared methods from
1936 * {@code Object}. Therefore, if no methods are explicitly declared in
1937 * this interface or any of its superinterfaces then the returned array
1938 * has length 0. (Note that a {@code Class} object which represents a class
1939 * always has public methods, inherited from {@code Object}.)
1940 *
1941 * <p> The returned array never contains methods with names {@value
1942 * ConstantDescs#INIT_NAME} or {@value ConstantDescs#CLASS_INIT_NAME}.
1943 *
1944 * <p> The elements in the returned array are not sorted and are not in any
1945 * particular order.
1946 *
1947 * <p> Generally, the result is computed as with the following 4 step algorithm.
1948 * Let C be the class or interface represented by this {@code Class} object:
1949 * <ol>
1950 * <li> A union of methods is composed of:
1951 * <ol type="a">
1952 * <li> C's declared public instance and static methods as returned by
1953 * {@link #getDeclaredMethods()} and filtered to include only public
1954 * methods.</li>
1955 * <li> If C is a class other than {@code Object}, then include the result
1956 * of invoking this algorithm recursively on the superclass of C.</li>
1957 * <li> Include the results of invoking this algorithm recursively on all
1958 * direct superinterfaces of C, but include only instance methods.</li>
1959 * </ol></li>
1960 * <li> Union from step 1 is partitioned into subsets of methods with same
1961 * signature (name, parameter types) and return type.</li>
1962 * <li> Within each such subset only the most specific methods are selected.
1963 * Let method M be a method from a set of methods with same signature
1964 * and return type. M is most specific if there is no such method
1965 * N != M from the same set, such that N is more specific than M.
1966 * N is more specific than M if:
1967 * <ol type="a">
1968 * <li> N is declared by a class and M is declared by an interface; or</li>
1969 * <li> N and M are both declared by classes or both by interfaces and
1970 * N's declaring type is the same as or a subtype of M's declaring type
1971 * (clearly, if M's and N's declaring types are the same type, then
1972 * M and N are the same method).</li>
1973 * </ol></li>
1974 * <li> The result of this algorithm is the union of all selected methods from
1975 * step 3.</li>
1976 * </ol>
1977 *
1978 * @apiNote There may be more than one method with a particular name
1979 * and parameter types in a class because while the Java language forbids a
1980 * class to declare multiple methods with the same signature but different
1981 * return types, the Java virtual machine does not. This
1982 * increased flexibility in the virtual machine can be used to
1983 * implement various language features. For example, covariant
1984 * returns can be implemented with {@linkplain
1985 * java.lang.reflect.Method#isBridge bridge methods}; the bridge
1986 * method and the overriding method would have the same
1987 * signature but different return types.
1988 *
1989 * @return the array of {@code Method} objects representing the
1990 * public methods of this class
1991 *
1992 * @jls 8.2 Class Members
1993 * @jls 8.4 Method Declarations
1994 * @since 1.1
1995 */
1996 public Method[] getMethods() {
1997 return copyMethods(privateGetPublicMethods());
1998 }
1999
2000
2001 /**
2002 * Returns an array containing {@code Constructor} objects reflecting
2003 * all the public constructors of the class represented by this
2004 * {@code Class} object. An array of length 0 is returned if the
2005 * class has no public constructors, or if the class is an array class, or
2006 * if the class reflects a primitive type or void.
2007 *
2008 * @apiNote
2009 * While this method returns an array of {@code
2010 * Constructor<T>} objects (that is an array of constructors from
2011 * this class), the return type of this method is {@code
2012 * Constructor<?>[]} and <em>not</em> {@code Constructor<T>[]} as
2013 * might be expected. This less informative return type is
2014 * necessary since after being returned from this method, the
2015 * array could be modified to hold {@code Constructor} objects for
2016 * different classes, which would violate the type guarantees of
2017 * {@code Constructor<T>[]}.
2018 *
2019 * @return the array of {@code Constructor} objects representing the
2020 * public constructors of this class
2021 *
2022 * @see #getDeclaredConstructors()
2023 * @since 1.1
2024 */
2025 public Constructor<?>[] getConstructors() {
2026 return copyConstructors(privateGetDeclaredConstructors(true));
2027 }
2028
2029
2030 /**
2031 * Returns a {@code Field} object that reflects the specified public member
2032 * field of the class or interface represented by this {@code Class}
2033 * object. The {@code name} parameter is a {@code String} specifying the
2034 * simple name of the desired field.
2035 *
2036 * <p> The field to be reflected is determined by the algorithm that
2037 * follows. Let C be the class or interface represented by this {@code Class} object:
2038 *
2039 * <OL>
2040 * <LI> If C declares a public field with the name specified, that is the
2041 * field to be reflected.</LI>
2042 * <LI> If no field was found in step 1 above, this algorithm is applied
2043 * recursively to each direct superinterface of C. The direct
2044 * superinterfaces are searched in the order they were declared.</LI>
2045 * <LI> If no field was found in steps 1 and 2 above, and C has a
2046 * superclass S, then this algorithm is invoked recursively upon S.
2047 * If C has no superclass, then a {@code NoSuchFieldException}
2048 * is thrown.</LI>
2049 * </OL>
2050 *
2051 * <p> If this {@code Class} object represents an array type, then this
2052 * method does not find the {@code length} field of the array type.
2053 *
2054 * @param name the field name
2055 * @return the {@code Field} object of this class specified by
2056 * {@code name}
2057 * @throws NoSuchFieldException if a field with the specified name is
2058 * not found.
2059 *
2060 * @since 1.1
2061 * @jls 8.2 Class Members
2062 * @jls 8.3 Field Declarations
2063 */
2064 public Field getField(String name) throws NoSuchFieldException {
2065 Objects.requireNonNull(name);
2066 Field field = getField0(name);
2067 if (field == null) {
2068 throw new NoSuchFieldException(name);
2069 }
2070 return getReflectionFactory().copyField(field);
2071 }
2072
2073
2074 /**
2075 * Returns a {@code Method} object that reflects the specified public
2076 * member method of the class or interface represented by this
2077 * {@code Class} object. The {@code name} parameter is a
2078 * {@code String} specifying the simple name of the desired method. The
2079 * {@code parameterTypes} parameter is an array of {@code Class}
2080 * objects that identify the method's formal parameter types, in declared
2081 * order. If {@code parameterTypes} is {@code null}, it is
2082 * treated as if it were an empty array.
2083 *
2084 * <p> If this {@code Class} object represents an array type, then this
2085 * method finds any public method inherited by the array type from
2086 * {@code Object} except method {@code clone()}.
2087 *
2088 * <p> If this {@code Class} object represents an interface then this
2089 * method does not find any implicitly declared method from
2090 * {@code Object}. Therefore, if no methods are explicitly declared in
2091 * this interface or any of its superinterfaces, then this method does not
2092 * find any method.
2093 *
2094 * <p> This method does not find any method with name {@value
2095 * ConstantDescs#INIT_NAME} or {@value ConstantDescs#CLASS_INIT_NAME}.
2096 *
2097 * <p> Generally, the method to be reflected is determined by the 4 step
2098 * algorithm that follows.
2099 * Let C be the class or interface represented by this {@code Class} object:
2100 * <ol>
2101 * <li> A union of methods is composed of:
2102 * <ol type="a">
2103 * <li> C's declared public instance and static methods as returned by
2104 * {@link #getDeclaredMethods()} and filtered to include only public
2105 * methods that match given {@code name} and {@code parameterTypes}</li>
2106 * <li> If C is a class other than {@code Object}, then include the result
2107 * of invoking this algorithm recursively on the superclass of C.</li>
2108 * <li> Include the results of invoking this algorithm recursively on all
2109 * direct superinterfaces of C, but include only instance methods.</li>
2110 * </ol></li>
2111 * <li> This union is partitioned into subsets of methods with same
2112 * return type (the selection of methods from step 1 also guarantees that
2113 * they have the same method name and parameter types).</li>
2114 * <li> Within each such subset only the most specific methods are selected.
2115 * Let method M be a method from a set of methods with same VM
2116 * signature (return type, name, parameter types).
2117 * M is most specific if there is no such method N != M from the same
2118 * set, such that N is more specific than M. N is more specific than M
2119 * if:
2120 * <ol type="a">
2121 * <li> N is declared by a class and M is declared by an interface; or</li>
2122 * <li> N and M are both declared by classes or both by interfaces and
2123 * N's declaring type is the same as or a subtype of M's declaring type
2124 * (clearly, if M's and N's declaring types are the same type, then
2125 * M and N are the same method).</li>
2126 * </ol></li>
2127 * <li> The result of this algorithm is chosen arbitrarily from the methods
2128 * with most specific return type among all selected methods from step 3.
2129 * Let R be a return type of a method M from the set of all selected methods
2130 * from step 3. M is a method with most specific return type if there is
2131 * no such method N != M from the same set, having return type S != R,
2132 * such that S is a subtype of R as determined by
2133 * R.class.{@link #isAssignableFrom}(S.class).
2134 * </ol>
2135 *
2136 * @apiNote There may be more than one method with matching name and
2137 * parameter types in a class because while the Java language forbids a
2138 * class to declare multiple methods with the same signature but different
2139 * return types, the Java virtual machine does not. This
2140 * increased flexibility in the virtual machine can be used to
2141 * implement various language features. For example, covariant
2142 * returns can be implemented with {@linkplain
2143 * java.lang.reflect.Method#isBridge bridge methods}; the bridge
2144 * method and the overriding method would have the same
2145 * signature but different return types. This method would return the
2146 * overriding method as it would have a more specific return type.
2147 *
2148 * @param name the name of the method
2149 * @param parameterTypes the list of parameters, may be {@code null}
2150 * @return the {@code Method} object that matches the specified
2151 * {@code name} and {@code parameterTypes}
2152 * @throws NoSuchMethodException if a matching method is not found,
2153 * if {@code parameterTypes} contains {@code null},
2154 * or if the name is {@value ConstantDescs#INIT_NAME} or
2155 * {@value ConstantDescs#CLASS_INIT_NAME}
2156 *
2157 * @jls 8.2 Class Members
2158 * @jls 8.4 Method Declarations
2159 * @since 1.1
2160 */
2161 public Method getMethod(String name, Class<?>... parameterTypes)
2162 throws NoSuchMethodException {
2163 Objects.requireNonNull(name);
2164 Method method = getMethod0(name, parameterTypes);
2165 if (method == null) {
2166 throw new NoSuchMethodException(methodToString(name, parameterTypes));
2167 }
2168 return getReflectionFactory().copyMethod(method);
2169 }
2170
2171 /**
2172 * Returns a {@code Constructor} object that reflects the specified
2173 * public constructor of the class represented by this {@code Class}
2174 * object. The {@code parameterTypes} parameter is an array of
2175 * {@code Class} objects that identify the constructor's formal
2176 * parameter types, in declared order.
2177 *
2178 * If this {@code Class} object represents an inner class
2179 * declared in a non-static context, the formal parameter types
2180 * include the explicit enclosing instance as the first parameter.
2181 *
2182 * <p> The constructor to reflect is the public constructor of the class
2183 * represented by this {@code Class} object whose formal parameter
2184 * types match those specified by {@code parameterTypes}.
2185 *
2186 * @param parameterTypes the parameter array, may be {@code null}
2187 * @return the {@code Constructor} object of the public constructor that
2188 * matches the specified {@code parameterTypes}
2189 * @throws NoSuchMethodException if a matching constructor is not found,
2190 * if this {@code Class} object represents an interface, a primitive
2191 * type, an array class, or void, or if {@code parameterTypes}
2192 * contains {@code null}
2193 *
2194 * @see #getDeclaredConstructor(Class[])
2195 * @since 1.1
2196 */
2197 public Constructor<T> getConstructor(Class<?>... parameterTypes)
2198 throws NoSuchMethodException {
2199 return getReflectionFactory().copyConstructor(
2200 getConstructor0(parameterTypes, Member.PUBLIC));
2201 }
2202
2203
2204 /**
2205 * Returns an array of {@code Class} objects reflecting all the
2206 * classes and interfaces declared as members of the class represented by
2207 * this {@code Class} object. This includes public, protected, default
2208 * (package) access, and private classes and interfaces declared by the
2209 * class, but excludes inherited classes and interfaces. This method
2210 * returns an array of length 0 if the class declares no classes or
2211 * interfaces as members, or if this {@code Class} object represents a
2212 * primitive type, an array class, or void.
2213 *
2214 * @return the array of {@code Class} objects representing all the
2215 * declared members of this class
2216 *
2217 * @since 1.1
2218 * @jls 8.5 Member Class and Interface Declarations
2219 */
2220 public Class<?>[] getDeclaredClasses() {
2221 return getDeclaredClasses0();
2222 }
2223
2224
2225 /**
2226 * Returns an array of {@code Field} objects reflecting all the fields
2227 * declared by the class or interface represented by this
2228 * {@code Class} object. This includes public, protected, default
2229 * (package) access, and private fields, but excludes inherited fields.
2230 *
2231 * <p> If this {@code Class} object represents a class or interface with no
2232 * declared fields, then this method returns an array of length 0.
2233 *
2234 * <p> If this {@code Class} object represents an array type, a primitive
2235 * type, or void, then this method returns an array of length 0.
2236 *
2237 * <p> The elements in the returned array are not sorted and are not in any
2238 * particular order.
2239 *
2240 * @return the array of {@code Field} objects representing all the
2241 * declared fields of this class
2242 *
2243 * @since 1.1
2244 * @jls 8.2 Class Members
2245 * @jls 8.3 Field Declarations
2246 */
2247 public Field[] getDeclaredFields() {
2248 return copyFields(privateGetDeclaredFields(false));
2249 }
2250
2251 /**
2252 * Returns an array of {@code RecordComponent} objects representing all the
2253 * record components of this record class, or {@code null} if this class is
2254 * not a record class.
2255 *
2256 * <p> The components are returned in the same order that they are declared
2257 * in the record header. The array is empty if this record class has no
2258 * components. If the class is not a record class, that is {@link
2259 * #isRecord()} returns {@code false}, then this method returns {@code null}.
2260 * Conversely, if {@link #isRecord()} returns {@code true}, then this method
2261 * returns a non-null value.
2262 *
2263 * @apiNote
2264 * <p> The following method can be used to find the record canonical constructor:
2265 *
2266 * {@snippet lang="java" :
2267 * static <T extends Record> Constructor<T> getCanonicalConstructor(Class<T> cls)
2268 * throws NoSuchMethodException {
2269 * Class<?>[] paramTypes =
2270 * Arrays.stream(cls.getRecordComponents())
2271 * .map(RecordComponent::getType)
2272 * .toArray(Class<?>[]::new);
2273 * return cls.getDeclaredConstructor(paramTypes);
2274 * }}
2275 *
2276 * @return An array of {@code RecordComponent} objects representing all the
2277 * record components of this record class, or {@code null} if this
2278 * class is not a record class
2279 *
2280 * @jls 8.10 Record Classes
2281 * @since 16
2282 */
2283 public RecordComponent[] getRecordComponents() {
2284 if (!isRecord()) {
2285 return null;
2286 }
2287 return getRecordComponents0();
2288 }
2289
2290 /**
2291 * Returns an array containing {@code Method} objects reflecting all the
2292 * declared methods of the class or interface represented by this {@code
2293 * Class} object, including public, protected, default (package)
2294 * access, and private methods, but excluding inherited methods.
2295 * The declared methods may include methods <em>not</em> in the
2296 * source of the class or interface, including {@linkplain
2297 * Method#isBridge bridge methods} and other {@linkplain
2298 * Executable#isSynthetic synthetic} methods added by compilers.
2299 *
2300 * <p> If this {@code Class} object represents a class or interface that
2301 * has multiple declared methods with the same name and parameter types,
2302 * but different return types, then the returned array has a {@code Method}
2303 * object for each such method.
2304 *
2305 * <p> If this {@code Class} object represents a class or interface that
2306 * has a class initialization method {@value ConstantDescs#CLASS_INIT_NAME},
2307 * then the returned array does <em>not</em> have a corresponding {@code
2308 * Method} object.
2309 *
2310 * <p> If this {@code Class} object represents a class or interface with no
2311 * declared methods, then the returned array has length 0.
2312 *
2313 * <p> If this {@code Class} object represents an array type, a primitive
2314 * type, or void, then the returned array has length 0.
2315 *
2316 * <p> The elements in the returned array are not sorted and are not in any
2317 * particular order.
2318 *
2319 * @return the array of {@code Method} objects representing all the
2320 * declared methods of this class
2321 *
2322 * @jls 8.2 Class Members
2323 * @jls 8.4 Method Declarations
2324 * @see <a
2325 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
2326 * programming language and JVM modeling in core reflection</a>
2327 * @since 1.1
2328 */
2329 public Method[] getDeclaredMethods() {
2330 return copyMethods(privateGetDeclaredMethods(false));
2331 }
2332
2333 /**
2334 * Returns an array of {@code Constructor} objects reflecting all the
2335 * constructors implicitly or explicitly declared by the class represented by this
2336 * {@code Class} object. These are public, protected, default
2337 * (package) access, and private constructors. The elements in the array
2338 * returned are not sorted and are not in any particular order. If the
2339 * class has a default constructor (JLS {@jls 8.8.9}), it is included in the returned array.
2340 * If a record class has a canonical constructor (JLS {@jls
2341 * 8.10.4.1}, {@jls 8.10.4.2}), it is included in the returned array.
2342 *
2343 * This method returns an array of length 0 if this {@code Class}
2344 * object represents an interface, a primitive type, an array class, or
2345 * void.
2346 *
2347 * @return the array of {@code Constructor} objects representing all the
2348 * declared constructors of this class
2349 *
2350 * @since 1.1
2351 * @see #getConstructors()
2352 * @jls 8.8 Constructor Declarations
2353 */
2354 public Constructor<?>[] getDeclaredConstructors() {
2355 return copyConstructors(privateGetDeclaredConstructors(false));
2356 }
2357
2358
2359 /**
2360 * Returns a {@code Field} object that reflects the specified declared
2361 * field of the class or interface represented by this {@code Class}
2362 * object. The {@code name} parameter is a {@code String} that specifies
2363 * the simple name of the desired field.
2364 *
2365 * <p> If this {@code Class} object represents an array type, then this
2366 * method does not find the {@code length} field of the array type.
2367 *
2368 * @param name the name of the field
2369 * @return the {@code Field} object for the specified field in this
2370 * class
2371 * @throws NoSuchFieldException if a field with the specified name is
2372 * not found.
2373 *
2374 * @since 1.1
2375 * @jls 8.2 Class Members
2376 * @jls 8.3 Field Declarations
2377 */
2378 public Field getDeclaredField(String name) throws NoSuchFieldException {
2379 Objects.requireNonNull(name);
2380 Field field = searchFields(privateGetDeclaredFields(false), name);
2381 if (field == null) {
2382 throw new NoSuchFieldException(name);
2383 }
2384 return getReflectionFactory().copyField(field);
2385 }
2386
2387
2388 /**
2389 * Returns a {@code Method} object that reflects the specified
2390 * declared method of the class or interface represented by this
2391 * {@code Class} object. The {@code name} parameter is a
2392 * {@code String} that specifies the simple name of the desired
2393 * method, and the {@code parameterTypes} parameter is an array of
2394 * {@code Class} objects that identify the method's formal parameter
2395 * types, in declared order. If more than one method with the same
2396 * parameter types is declared in a class, and one of these methods has a
2397 * return type that is more specific than any of the others, that method is
2398 * returned; otherwise one of the methods is chosen arbitrarily. If the
2399 * name is {@value ConstantDescs#INIT_NAME} or {@value
2400 * ConstantDescs#CLASS_INIT_NAME} a {@code NoSuchMethodException}
2401 * is raised.
2402 *
2403 * <p> If this {@code Class} object represents an array type, then this
2404 * method does not find the {@code clone()} method.
2405 *
2406 * @param name the name of the method
2407 * @param parameterTypes the parameter array, may be {@code null}
2408 * @return the {@code Method} object for the method of this class
2409 * matching the specified name and parameters
2410 * @throws NoSuchMethodException if a matching method is not found,
2411 * if {@code parameterTypes} contains {@code null},
2412 * or if the name is {@value ConstantDescs#INIT_NAME} or
2413 * {@value ConstantDescs#CLASS_INIT_NAME}
2414 *
2415 * @jls 8.2 Class Members
2416 * @jls 8.4 Method Declarations
2417 * @since 1.1
2418 */
2419 public Method getDeclaredMethod(String name, Class<?>... parameterTypes)
2420 throws NoSuchMethodException {
2421 Objects.requireNonNull(name);
2422 Method method = searchMethods(privateGetDeclaredMethods(false), name, parameterTypes);
2423 if (method == null) {
2424 throw new NoSuchMethodException(methodToString(name, parameterTypes));
2425 }
2426 return getReflectionFactory().copyMethod(method);
2427 }
2428
2429 /**
2430 * Returns the list of {@code Method} objects for the declared public
2431 * methods of this class or interface that have the specified method name
2432 * and parameter types.
2433 *
2434 * @param name the name of the method
2435 * @param parameterTypes the parameter array
2436 * @return the list of {@code Method} objects for the public methods of
2437 * this class matching the specified name and parameters
2438 */
2439 List<Method> getDeclaredPublicMethods(String name, Class<?>... parameterTypes) {
2440 Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true);
2441 ReflectionFactory factory = getReflectionFactory();
2442 List<Method> result = new ArrayList<>();
2443 for (Method method : methods) {
2444 if (method.getName().equals(name)
2445 && Arrays.equals(
2446 factory.getExecutableSharedParameterTypes(method),
2447 parameterTypes)) {
2448 result.add(factory.copyMethod(method));
2449 }
2450 }
2451 return result;
2452 }
2453
2454 /**
2455 * Returns the most specific {@code Method} object of this class, super class or
2456 * interface that have the specified method name and parameter types.
2457 *
2458 * @param publicOnly true if only public methods are examined, otherwise all methods
2459 * @param name the name of the method
2460 * @param parameterTypes the parameter array
2461 * @return the {@code Method} object for the method found from this class matching
2462 * the specified name and parameters, or null if not found
2463 */
2464 Method findMethod(boolean publicOnly, String name, Class<?>... parameterTypes) {
2465 PublicMethods.MethodList res = getMethodsRecursive(name, parameterTypes, true, publicOnly);
2466 return res == null ? null : getReflectionFactory().copyMethod(res.getMostSpecific());
2467 }
2468
2469 /**
2470 * Returns a {@code Constructor} object that reflects the specified
2471 * constructor of the class represented by this
2472 * {@code Class} object. The {@code parameterTypes} parameter is
2473 * an array of {@code Class} objects that identify the constructor's
2474 * formal parameter types, in declared order.
2475 *
2476 * If this {@code Class} object represents an inner class
2477 * declared in a non-static context, the formal parameter types
2478 * include the explicit enclosing instance as the first parameter.
2479 *
2480 * @param parameterTypes the parameter array, may be {@code null}
2481 * @return The {@code Constructor} object for the constructor with the
2482 * specified parameter list
2483 * @throws NoSuchMethodException if a matching constructor is not found,
2484 * if this {@code Class} object represents an interface, a
2485 * primitive type, an array class, or void, or if
2486 * {@code parameterTypes} contains {@code null}
2487 *
2488 * @see #getConstructor(Class[])
2489 * @since 1.1
2490 */
2491 public Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes)
2492 throws NoSuchMethodException {
2493 return getReflectionFactory().copyConstructor(
2494 getConstructor0(parameterTypes, Member.DECLARED));
2495 }
2496
2497 /**
2498 * Finds a resource with a given name.
2499 *
2500 * <p> If this class is in a named {@link Module Module} then this method
2501 * will attempt to find the resource in the module. This is done by
2502 * delegating to the module's class loader {@link
2503 * ClassLoader#findResource(String,String) findResource(String,String)}
2504 * method, invoking it with the module name and the absolute name of the
2505 * resource. Resources in named modules are subject to the rules for
2506 * encapsulation specified in the {@code Module} {@link
2507 * Module#getResourceAsStream getResourceAsStream} method and so this
2508 * method returns {@code null} when the resource is a
2509 * non-"{@code .class}" resource in a package that is not open to the
2510 * caller's module.
2511 *
2512 * <p> Otherwise, if this class is not in a named module then the rules for
2513 * searching resources associated with a given class are implemented by the
2514 * defining {@linkplain ClassLoader class loader} of the class. This method
2515 * delegates to this {@code Class} object's class loader.
2516 * If this {@code Class} object was loaded by the bootstrap class loader,
2517 * the method delegates to {@link ClassLoader#getSystemResourceAsStream}.
2518 *
2519 * <p> Before delegation, an absolute resource name is constructed from the
2520 * given resource name using this algorithm:
2521 *
2522 * <ul>
2523 *
2524 * <li> If the {@code name} begins with a {@code '/'}
2525 * (<code>'\u002f'</code>), then the absolute name of the resource is the
2526 * portion of the {@code name} following the {@code '/'}.
2527 *
2528 * <li> Otherwise, the absolute name is of the following form:
2529 *
2530 * <blockquote>
2531 * {@code modified_package_name/name}
2532 * </blockquote>
2533 *
2534 * <p> Where the {@code modified_package_name} is the package name of this
2535 * object with {@code '/'} substituted for {@code '.'}
2536 * (<code>'\u002e'</code>).
2537 *
2538 * </ul>
2539 *
2540 * @param name name of the desired resource
2541 * @return A {@link java.io.InputStream} object; {@code null} if no
2542 * resource with this name is found, or the resource is in a package
2543 * that is not {@linkplain Module#isOpen(String, Module) open} to at
2544 * least the caller module.
2545 *
2546 * @see Module#getResourceAsStream(String)
2547 * @since 1.1
2548 */
2549 @CallerSensitive
2550 public InputStream getResourceAsStream(String name) {
2551 name = resolveName(name);
2552
2553 Module thisModule = getModule();
2554 if (thisModule.isNamed()) {
2555 // check if resource can be located by caller
2556 if (Resources.canEncapsulate(name)
2557 && !isOpenToCaller(name, Reflection.getCallerClass())) {
2558 return null;
2559 }
2560
2561 // resource not encapsulated or in package open to caller
2562 String mn = thisModule.getName();
2563 ClassLoader cl = classLoader;
2564 try {
2565
2566 // special-case built-in class loaders to avoid the
2567 // need for a URL connection
2568 if (cl == null) {
2569 return BootLoader.findResourceAsStream(mn, name);
2570 } else if (cl instanceof BuiltinClassLoader bcl) {
2571 return bcl.findResourceAsStream(mn, name);
2572 } else {
2573 URL url = cl.findResource(mn, name);
2574 return (url != null) ? url.openStream() : null;
2575 }
2576
2577 } catch (IOException | SecurityException e) {
2578 return null;
2579 }
2580 }
2581
2582 // unnamed module
2583 ClassLoader cl = classLoader;
2584 if (cl == null) {
2585 return ClassLoader.getSystemResourceAsStream(name);
2586 } else {
2587 return cl.getResourceAsStream(name);
2588 }
2589 }
2590
2591 /**
2592 * Finds a resource with a given name.
2593 *
2594 * <p> If this class is in a named {@link Module Module} then this method
2595 * will attempt to find the resource in the module. This is done by
2596 * delegating to the module's class loader {@link
2597 * ClassLoader#findResource(String,String) findResource(String,String)}
2598 * method, invoking it with the module name and the absolute name of the
2599 * resource. Resources in named modules are subject to the rules for
2600 * encapsulation specified in the {@code Module} {@link
2601 * Module#getResourceAsStream getResourceAsStream} method and so this
2602 * method returns {@code null} when the resource is a
2603 * non-"{@code .class}" resource in a package that is not open to the
2604 * caller's module.
2605 *
2606 * <p> Otherwise, if this class is not in a named module then the rules for
2607 * searching resources associated with a given class are implemented by the
2608 * defining {@linkplain ClassLoader class loader} of the class. This method
2609 * delegates to this {@code Class} object's class loader.
2610 * If this {@code Class} object was loaded by the bootstrap class loader,
2611 * the method delegates to {@link ClassLoader#getSystemResource}.
2612 *
2613 * <p> Before delegation, an absolute resource name is constructed from the
2614 * given resource name using this algorithm:
2615 *
2616 * <ul>
2617 *
2618 * <li> If the {@code name} begins with a {@code '/'}
2619 * (<code>'\u002f'</code>), then the absolute name of the resource is the
2620 * portion of the {@code name} following the {@code '/'}.
2621 *
2622 * <li> Otherwise, the absolute name is of the following form:
2623 *
2624 * <blockquote>
2625 * {@code modified_package_name/name}
2626 * </blockquote>
2627 *
2628 * <p> Where the {@code modified_package_name} is the package name of this
2629 * object with {@code '/'} substituted for {@code '.'}
2630 * (<code>'\u002e'</code>).
2631 *
2632 * </ul>
2633 *
2634 * @param name name of the desired resource
2635 * @return A {@link java.net.URL} object; {@code null} if no resource with
2636 * this name is found, the resource cannot be located by a URL, or the
2637 * resource is in a package that is not
2638 * {@linkplain Module#isOpen(String, Module) open} to at least the caller
2639 * module.
2640 * @since 1.1
2641 */
2642 @CallerSensitive
2643 public URL getResource(String name) {
2644 name = resolveName(name);
2645
2646 Module thisModule = getModule();
2647 if (thisModule.isNamed()) {
2648 // check if resource can be located by caller
2649 if (Resources.canEncapsulate(name)
2650 && !isOpenToCaller(name, Reflection.getCallerClass())) {
2651 return null;
2652 }
2653
2654 // resource not encapsulated or in package open to caller
2655 String mn = thisModule.getName();
2656 ClassLoader cl = classLoader;
2657 try {
2658 if (cl == null) {
2659 return BootLoader.findResource(mn, name);
2660 } else {
2661 return cl.findResource(mn, name);
2662 }
2663 } catch (IOException ioe) {
2664 return null;
2665 }
2666 }
2667
2668 // unnamed module
2669 ClassLoader cl = classLoader;
2670 if (cl == null) {
2671 return ClassLoader.getSystemResource(name);
2672 } else {
2673 return cl.getResource(name);
2674 }
2675 }
2676
2677 /**
2678 * Returns true if a resource with the given name can be located by the
2679 * given caller. All resources in a module can be located by code in
2680 * the module. For other callers, then the package needs to be open to
2681 * the caller.
2682 */
2683 private boolean isOpenToCaller(String name, Class<?> caller) {
2684 // assert getModule().isNamed();
2685 Module thisModule = getModule();
2686 Module callerModule = (caller != null) ? caller.getModule() : null;
2687 if (callerModule != thisModule) {
2688 String pn = Resources.toPackageName(name);
2689 if (thisModule.getDescriptor().packages().contains(pn)) {
2690 if (callerModule == null) {
2691 // no caller, return true if the package is open to all modules
2692 return thisModule.isOpen(pn);
2693 }
2694 if (!thisModule.isOpen(pn, callerModule)) {
2695 // package not open to caller
2696 return false;
2697 }
2698 }
2699 }
2700 return true;
2701 }
2702
2703 private transient final ProtectionDomain protectionDomain;
2704
2705 /** Holder for the protection domain returned when the internal domain is null */
2706 private static class Holder {
2707 private static final ProtectionDomain allPermDomain;
2708 static {
2709 Permissions perms = new Permissions();
2710 perms.add(new AllPermission());
2711 allPermDomain = new ProtectionDomain(null, perms);
2712 }
2713 }
2714
2715 /**
2716 * Returns the {@code ProtectionDomain} of this class.
2717 *
2718 * @return the ProtectionDomain of this class
2719 *
2720 * @see java.security.ProtectionDomain
2721 * @since 1.2
2722 */
2723 public ProtectionDomain getProtectionDomain() {
2724 if (protectionDomain == null) {
2725 return Holder.allPermDomain;
2726 } else {
2727 return protectionDomain;
2728 }
2729 }
2730
2731 /*
2732 * Returns the Class object for the named primitive type. Type parameter T
2733 * avoids redundant casts for trusted code.
2734 */
2735 static native <T> Class<T> getPrimitiveClass(String name);
2736
2737 /**
2738 * Add a package name prefix if the name is not absolute. Remove leading "/"
2739 * if name is absolute
2740 */
2741 private String resolveName(String name) {
2742 if (!name.startsWith("/")) {
2743 String baseName = getPackageName();
2744 if (!baseName.isEmpty()) {
2745 int len = baseName.length() + 1 + name.length();
2746 StringBuilder sb = new StringBuilder(len);
2747 name = sb.append(baseName.replace('.', '/'))
2748 .append('/')
2749 .append(name)
2750 .toString();
2751 }
2752 } else {
2753 name = name.substring(1);
2754 }
2755 return name;
2756 }
2757
2758 /**
2759 * Atomic operations support.
2760 */
2761 private static class Atomic {
2762 // initialize Unsafe machinery here, since we need to call Class.class instance method
2763 // and have to avoid calling it in the static initializer of the Class class...
2764 private static final Unsafe unsafe = Unsafe.getUnsafe();
2765 // offset of Class.reflectionData instance field
2766 private static final long reflectionDataOffset
2767 = unsafe.objectFieldOffset(Class.class, "reflectionData");
2768 // offset of Class.annotationType instance field
2769 private static final long annotationTypeOffset
2770 = unsafe.objectFieldOffset(Class.class, "annotationType");
2771 // offset of Class.annotationData instance field
2772 private static final long annotationDataOffset
2773 = unsafe.objectFieldOffset(Class.class, "annotationData");
2774
2775 static <T> boolean casReflectionData(Class<?> clazz,
2776 SoftReference<ReflectionData<T>> oldData,
2777 SoftReference<ReflectionData<T>> newData) {
2778 return unsafe.compareAndSetReference(clazz, reflectionDataOffset, oldData, newData);
2779 }
2780
2781 static boolean casAnnotationType(Class<?> clazz,
2782 AnnotationType oldType,
2783 AnnotationType newType) {
2784 return unsafe.compareAndSetReference(clazz, annotationTypeOffset, oldType, newType);
2785 }
2786
2787 static boolean casAnnotationData(Class<?> clazz,
2788 AnnotationData oldData,
2789 AnnotationData newData) {
2790 return unsafe.compareAndSetReference(clazz, annotationDataOffset, oldData, newData);
2791 }
2792 }
2793
2794 /**
2795 * Reflection support.
2796 */
2797
2798 // Reflection data caches various derived names and reflective members. Cached
2799 // values may be invalidated when JVM TI RedefineClasses() is called
2800 private static class ReflectionData<T> {
2801 volatile Field[] declaredFields;
2802 volatile Field[] publicFields;
2803 volatile Method[] declaredMethods;
2804 volatile Method[] publicMethods;
2805 volatile Constructor<T>[] declaredConstructors;
2806 volatile Constructor<T>[] publicConstructors;
2807 // Intermediate results for getFields and getMethods
2808 volatile Field[] declaredPublicFields;
2809 volatile Method[] declaredPublicMethods;
2810 volatile Class<?>[] interfaces;
2811
2812 // Cached names
2813 String simpleName;
2814 String canonicalName;
2815 static final String NULL_SENTINEL = new String();
2816
2817 // Value of classRedefinedCount when we created this ReflectionData instance
2818 final int redefinedCount;
2819
2820 ReflectionData(int redefinedCount) {
2821 this.redefinedCount = redefinedCount;
2822 }
2823 }
2824
2825 private transient volatile SoftReference<ReflectionData<T>> reflectionData;
2826
2827 // Incremented by the VM on each call to JVM TI RedefineClasses()
2828 // that redefines this class or a superclass.
2829 private transient volatile int classRedefinedCount;
2830
2831 // Lazily create and cache ReflectionData
2832 private ReflectionData<T> reflectionData() {
2833 SoftReference<ReflectionData<T>> reflectionData = this.reflectionData;
2834 int classRedefinedCount = this.classRedefinedCount;
2835 ReflectionData<T> rd;
2836 if (reflectionData != null &&
2837 (rd = reflectionData.get()) != null &&
2838 rd.redefinedCount == classRedefinedCount) {
2839 return rd;
2840 }
2841 // else no SoftReference or cleared SoftReference or stale ReflectionData
2842 // -> create and replace new instance
2843 return newReflectionData(reflectionData, classRedefinedCount);
2844 }
2845
2846 private ReflectionData<T> newReflectionData(SoftReference<ReflectionData<T>> oldReflectionData,
2847 int classRedefinedCount) {
2848 while (true) {
2849 ReflectionData<T> rd = new ReflectionData<>(classRedefinedCount);
2850 // try to CAS it...
2851 if (Atomic.casReflectionData(this, oldReflectionData, new SoftReference<>(rd))) {
2852 return rd;
2853 }
2854 // else retry
2855 oldReflectionData = this.reflectionData;
2856 classRedefinedCount = this.classRedefinedCount;
2857 if (oldReflectionData != null &&
2858 (rd = oldReflectionData.get()) != null &&
2859 rd.redefinedCount == classRedefinedCount) {
2860 return rd;
2861 }
2862 }
2863 }
2864
2865 // Generic signature handling
2866 private native String getGenericSignature0();
2867
2868 // Generic info repository; lazily initialized
2869 private transient volatile ClassRepository genericInfo;
2870
2871 // accessor for factory
2872 private GenericsFactory getFactory() {
2873 // create scope and factory
2874 return CoreReflectionFactory.make(this, ClassScope.make(this));
2875 }
2876
2877 // accessor for generic info repository;
2878 // generic info is lazily initialized
2879 private ClassRepository getGenericInfo() {
2880 ClassRepository genericInfo = this.genericInfo;
2881 if (genericInfo == null) {
2882 String signature = getGenericSignature0();
2883 if (signature == null) {
2884 genericInfo = ClassRepository.NONE;
2885 } else {
2886 genericInfo = ClassRepository.make(signature, getFactory());
2887 }
2888 this.genericInfo = genericInfo;
2889 }
2890 return (genericInfo != ClassRepository.NONE) ? genericInfo : null;
2891 }
2892
2893 // Annotations handling
2894 native byte[] getRawAnnotations();
2895 // Since 1.8
2896 native byte[] getRawTypeAnnotations();
2897 static byte[] getExecutableTypeAnnotationBytes(Executable ex) {
2898 return getReflectionFactory().getExecutableTypeAnnotationBytes(ex);
2899 }
2900
2901 native ConstantPool getConstantPool();
2902
2903 //
2904 //
2905 // java.lang.reflect.Field handling
2906 //
2907 //
2908
2909 // Returns an array of "root" fields. These Field objects must NOT
2910 // be propagated to the outside world, but must instead be copied
2911 // via ReflectionFactory.copyField.
2912 private Field[] privateGetDeclaredFields(boolean publicOnly) {
2913 Field[] res;
2914 ReflectionData<T> rd = reflectionData();
2915 res = publicOnly ? rd.declaredPublicFields : rd.declaredFields;
2916 if (res != null) return res;
2917 // No cached value available; request value from VM
2918 res = Reflection.filterFields(this, getDeclaredFields0(publicOnly));
2919 if (publicOnly) {
2920 rd.declaredPublicFields = res;
2921 } else {
2922 rd.declaredFields = res;
2923 }
2924 return res;
2925 }
2926
2927 // Returns an array of "root" fields. These Field objects must NOT
2928 // be propagated to the outside world, but must instead be copied
2929 // via ReflectionFactory.copyField.
2930 private Field[] privateGetPublicFields() {
2931 Field[] res;
2932 ReflectionData<T> rd = reflectionData();
2933 res = rd.publicFields;
2934 if (res != null) return res;
2935
2936 // Use a linked hash set to ensure order is preserved and
2937 // fields from common super interfaces are not duplicated
2938 LinkedHashSet<Field> fields = new LinkedHashSet<>();
2939
2940 // Local fields
2941 addAll(fields, privateGetDeclaredFields(true));
2942
2943 // Direct superinterfaces, recursively
2944 for (Class<?> si : getInterfaces(/* cloneArray */ false)) {
2945 addAll(fields, si.privateGetPublicFields());
2946 }
2947
2948 // Direct superclass, recursively
2949 Class<?> sc = getSuperclass();
2950 if (sc != null) {
2951 addAll(fields, sc.privateGetPublicFields());
2952 }
2953
2954 res = fields.toArray(new Field[0]);
2955 rd.publicFields = res;
2956 return res;
2957 }
2958
2959 private static void addAll(Collection<Field> c, Field[] o) {
2960 for (Field f : o) {
2961 c.add(f);
2962 }
2963 }
2964
2965
2966 //
2967 //
2968 // java.lang.reflect.Constructor handling
2969 //
2970 //
2971
2972 // Returns an array of "root" constructors. These Constructor
2973 // objects must NOT be propagated to the outside world, but must
2974 // instead be copied via ReflectionFactory.copyConstructor.
2975 private Constructor<T>[] privateGetDeclaredConstructors(boolean publicOnly) {
2976 Constructor<T>[] res;
2977 ReflectionData<T> rd = reflectionData();
2978 res = publicOnly ? rd.publicConstructors : rd.declaredConstructors;
2979 if (res != null) return res;
2980 // No cached value available; request value from VM
2981 if (isInterface()) {
2982 @SuppressWarnings("unchecked")
2983 Constructor<T>[] temporaryRes = (Constructor<T>[]) new Constructor<?>[0];
2984 res = temporaryRes;
2985 } else {
2986 res = getDeclaredConstructors0(publicOnly);
2987 }
2988 if (publicOnly) {
2989 rd.publicConstructors = res;
2990 } else {
2991 rd.declaredConstructors = res;
2992 }
2993 return res;
2994 }
2995
2996 //
2997 //
2998 // java.lang.reflect.Method handling
2999 //
3000 //
3001
3002 // Returns an array of "root" methods. These Method objects must NOT
3003 // be propagated to the outside world, but must instead be copied
3004 // via ReflectionFactory.copyMethod.
3005 private Method[] privateGetDeclaredMethods(boolean publicOnly) {
3006 Method[] res;
3007 ReflectionData<T> rd = reflectionData();
3008 res = publicOnly ? rd.declaredPublicMethods : rd.declaredMethods;
3009 if (res != null) return res;
3010 // No cached value available; request value from VM
3011 res = Reflection.filterMethods(this, getDeclaredMethods0(publicOnly));
3012 if (publicOnly) {
3013 rd.declaredPublicMethods = res;
3014 } else {
3015 rd.declaredMethods = res;
3016 }
3017 return res;
3018 }
3019
3020 // Returns an array of "root" methods. These Method objects must NOT
3021 // be propagated to the outside world, but must instead be copied
3022 // via ReflectionFactory.copyMethod.
3023 private Method[] privateGetPublicMethods() {
3024 Method[] res;
3025 ReflectionData<T> rd = reflectionData();
3026 res = rd.publicMethods;
3027 if (res != null) return res;
3028
3029 // No cached value available; compute value recursively.
3030 // Start by fetching public declared methods...
3031 PublicMethods pms = new PublicMethods();
3032 for (Method m : privateGetDeclaredMethods(/* publicOnly */ true)) {
3033 pms.merge(m);
3034 }
3035 // ...then recur over superclass methods...
3036 Class<?> sc = getSuperclass();
3037 if (sc != null) {
3038 for (Method m : sc.privateGetPublicMethods()) {
3039 pms.merge(m);
3040 }
3041 }
3042 // ...and finally over direct superinterfaces.
3043 for (Class<?> intf : getInterfaces(/* cloneArray */ false)) {
3044 for (Method m : intf.privateGetPublicMethods()) {
3045 // static interface methods are not inherited
3046 if (!Modifier.isStatic(m.getModifiers())) {
3047 pms.merge(m);
3048 }
3049 }
3050 }
3051
3052 res = pms.toArray();
3053 rd.publicMethods = res;
3054 return res;
3055 }
3056
3057
3058 //
3059 // Helpers for fetchers of one field, method, or constructor
3060 //
3061
3062 // This method does not copy the returned Field object!
3063 private static Field searchFields(Field[] fields, String name) {
3064 for (Field field : fields) {
3065 if (field.getName().equals(name)) {
3066 return field;
3067 }
3068 }
3069 return null;
3070 }
3071
3072 // Returns a "root" Field object. This Field object must NOT
3073 // be propagated to the outside world, but must instead be copied
3074 // via ReflectionFactory.copyField.
3075 private Field getField0(String name) {
3076 // Note: the intent is that the search algorithm this routine
3077 // uses be equivalent to the ordering imposed by
3078 // privateGetPublicFields(). It fetches only the declared
3079 // public fields for each class, however, to reduce the number
3080 // of Field objects which have to be created for the common
3081 // case where the field being requested is declared in the
3082 // class which is being queried.
3083 Field res;
3084 // Search declared public fields
3085 if ((res = searchFields(privateGetDeclaredFields(true), name)) != null) {
3086 return res;
3087 }
3088 // Direct superinterfaces, recursively
3089 Class<?>[] interfaces = getInterfaces(/* cloneArray */ false);
3090 for (Class<?> c : interfaces) {
3091 if ((res = c.getField0(name)) != null) {
3092 return res;
3093 }
3094 }
3095 // Direct superclass, recursively
3096 if (!isInterface()) {
3097 Class<?> c = getSuperclass();
3098 if (c != null) {
3099 if ((res = c.getField0(name)) != null) {
3100 return res;
3101 }
3102 }
3103 }
3104 return null;
3105 }
3106
3107 // This method does not copy the returned Method object!
3108 private static Method searchMethods(Method[] methods,
3109 String name,
3110 Class<?>[] parameterTypes)
3111 {
3112 ReflectionFactory fact = getReflectionFactory();
3113 Method res = null;
3114 for (Method m : methods) {
3115 if (m.getName().equals(name)
3116 && arrayContentsEq(parameterTypes,
3117 fact.getExecutableSharedParameterTypes(m))
3118 && (res == null
3119 || (res.getReturnType() != m.getReturnType()
3120 && res.getReturnType().isAssignableFrom(m.getReturnType()))))
3121 res = m;
3122 }
3123 return res;
3124 }
3125
3126 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
3127
3128 // Returns a "root" Method object. This Method object must NOT
3129 // be propagated to the outside world, but must instead be copied
3130 // via ReflectionFactory.copyMethod.
3131 private Method getMethod0(String name, Class<?>[] parameterTypes) {
3132 PublicMethods.MethodList res = getMethodsRecursive(
3133 name,
3134 parameterTypes == null ? EMPTY_CLASS_ARRAY : parameterTypes,
3135 /* includeStatic */ true, /* publicOnly */ true);
3136 return res == null ? null : res.getMostSpecific();
3137 }
3138
3139 // Returns a list of "root" Method objects. These Method objects must NOT
3140 // be propagated to the outside world, but must instead be copied
3141 // via ReflectionFactory.copyMethod.
3142 private PublicMethods.MethodList getMethodsRecursive(String name,
3143 Class<?>[] parameterTypes,
3144 boolean includeStatic,
3145 boolean publicOnly) {
3146 // 1st check declared methods
3147 Method[] methods = privateGetDeclaredMethods(publicOnly);
3148 PublicMethods.MethodList res = PublicMethods.MethodList
3149 .filter(methods, name, parameterTypes, includeStatic);
3150 // if there is at least one match among declared methods, we need not
3151 // search any further as such match surely overrides matching methods
3152 // declared in superclass(es) or interface(s).
3153 if (res != null) {
3154 return res;
3155 }
3156
3157 // if there was no match among declared methods,
3158 // we must consult the superclass (if any) recursively...
3159 Class<?> sc = getSuperclass();
3160 if (sc != null) {
3161 res = sc.getMethodsRecursive(name, parameterTypes, includeStatic, publicOnly);
3162 }
3163
3164 // ...and coalesce the superclass methods with methods obtained
3165 // from directly implemented interfaces excluding static methods...
3166 for (Class<?> intf : getInterfaces(/* cloneArray */ false)) {
3167 res = PublicMethods.MethodList.merge(
3168 res, intf.getMethodsRecursive(name, parameterTypes, /* includeStatic */ false, publicOnly));
3169 }
3170
3171 return res;
3172 }
3173
3174 // Returns a "root" Constructor object. This Constructor object must NOT
3175 // be propagated to the outside world, but must instead be copied
3176 // via ReflectionFactory.copyConstructor.
3177 private Constructor<T> getConstructor0(Class<?>[] parameterTypes,
3178 int which) throws NoSuchMethodException
3179 {
3180 ReflectionFactory fact = getReflectionFactory();
3181 Constructor<T>[] constructors = privateGetDeclaredConstructors((which == Member.PUBLIC));
3182 for (Constructor<T> constructor : constructors) {
3183 if (arrayContentsEq(parameterTypes,
3184 fact.getExecutableSharedParameterTypes(constructor))) {
3185 return constructor;
3186 }
3187 }
3188 throw new NoSuchMethodException(methodToString("<init>", parameterTypes));
3189 }
3190
3191 //
3192 // Other helpers and base implementation
3193 //
3194
3195 private static boolean arrayContentsEq(Object[] a1, Object[] a2) {
3196 if (a1 == null) {
3197 return a2 == null || a2.length == 0;
3198 }
3199
3200 if (a2 == null) {
3201 return a1.length == 0;
3202 }
3203
3204 if (a1.length != a2.length) {
3205 return false;
3206 }
3207
3208 for (int i = 0; i < a1.length; i++) {
3209 if (a1[i] != a2[i]) {
3210 return false;
3211 }
3212 }
3213
3214 return true;
3215 }
3216
3217 private static Field[] copyFields(Field[] arg) {
3218 Field[] out = new Field[arg.length];
3219 ReflectionFactory fact = getReflectionFactory();
3220 for (int i = 0; i < arg.length; i++) {
3221 out[i] = fact.copyField(arg[i]);
3222 }
3223 return out;
3224 }
3225
3226 private static Method[] copyMethods(Method[] arg) {
3227 Method[] out = new Method[arg.length];
3228 ReflectionFactory fact = getReflectionFactory();
3229 for (int i = 0; i < arg.length; i++) {
3230 out[i] = fact.copyMethod(arg[i]);
3231 }
3232 return out;
3233 }
3234
3235 private static <U> Constructor<U>[] copyConstructors(Constructor<U>[] arg) {
3236 Constructor<U>[] out = arg.clone();
3237 ReflectionFactory fact = getReflectionFactory();
3238 for (int i = 0; i < out.length; i++) {
3239 out[i] = fact.copyConstructor(out[i]);
3240 }
3241 return out;
3242 }
3243
3244 private native Field[] getDeclaredFields0(boolean publicOnly);
3245 private native Method[] getDeclaredMethods0(boolean publicOnly);
3246 private native Constructor<T>[] getDeclaredConstructors0(boolean publicOnly);
3247 private native Class<?>[] getDeclaredClasses0();
3248
3249 /*
3250 * Returns an array containing the components of the Record attribute,
3251 * or null if the attribute is not present.
3252 *
3253 * Note that this method returns non-null array on a class with
3254 * the Record attribute even if this class is not a record.
3255 */
3256 private native RecordComponent[] getRecordComponents0();
3257 private native boolean isRecord0();
3258
3259 /**
3260 * Helper method to get the method name from arguments.
3261 */
3262 private String methodToString(String name, Class<?>[] argTypes) {
3263 return getName() + '.' + name +
3264 ((argTypes == null || argTypes.length == 0) ?
3265 "()" :
3266 Arrays.stream(argTypes)
3267 .map(c -> c == null ? "null" : c.getName())
3268 .collect(Collectors.joining(",", "(", ")")));
3269 }
3270
3271 /** use serialVersionUID from JDK 1.1 for interoperability */
3272 @java.io.Serial
3273 private static final long serialVersionUID = 3206093459760846163L;
3274
3275
3276 /**
3277 * Class Class is special cased within the Serialization Stream Protocol.
3278 *
3279 * A Class instance is written initially into an ObjectOutputStream in the
3280 * following format:
3281 * <pre>
3282 * {@code TC_CLASS} ClassDescriptor
3283 * A ClassDescriptor is a special cased serialization of
3284 * a {@code java.io.ObjectStreamClass} instance.
3285 * </pre>
3286 * A new handle is generated for the initial time the class descriptor
3287 * is written into the stream. Future references to the class descriptor
3288 * are written as references to the initial class descriptor instance.
3289 *
3290 * @see java.io.ObjectStreamClass
3291 */
3292 @java.io.Serial
3293 private static final ObjectStreamField[] serialPersistentFields =
3294 new ObjectStreamField[0];
3295
3296
3297 /**
3298 * Returns the assertion status that would be assigned to this
3299 * class if it were to be initialized at the time this method is invoked.
3300 * If this class has had its assertion status set, the most recent
3301 * setting will be returned; otherwise, if any package default assertion
3302 * status pertains to this class, the most recent setting for the most
3303 * specific pertinent package default assertion status is returned;
3304 * otherwise, if this class is not a system class (i.e., it has a
3305 * class loader) its class loader's default assertion status is returned;
3306 * otherwise, the system class default assertion status is returned.
3307 *
3308 * @apiNote
3309 * Few programmers will have any need for this method; it is provided
3310 * for the benefit of the JDK itself. (It allows a class to determine at
3311 * the time that it is initialized whether assertions should be enabled.)
3312 * Note that this method is not guaranteed to return the actual
3313 * assertion status that was (or will be) associated with the specified
3314 * class when it was (or will be) initialized.
3315 *
3316 * @return the desired assertion status of the specified class.
3317 * @see java.lang.ClassLoader#setClassAssertionStatus
3318 * @see java.lang.ClassLoader#setPackageAssertionStatus
3319 * @see java.lang.ClassLoader#setDefaultAssertionStatus
3320 * @since 1.4
3321 */
3322 public boolean desiredAssertionStatus() {
3323 ClassLoader loader = classLoader;
3324 // If the loader is null this is a system class, so ask the VM
3325 if (loader == null)
3326 return desiredAssertionStatus0(this);
3327
3328 // If the classloader has been initialized with the assertion
3329 // directives, ask it. Otherwise, ask the VM.
3330 synchronized(loader.assertionLock) {
3331 if (loader.classAssertionStatus != null) {
3332 return loader.desiredAssertionStatus(getName());
3333 }
3334 }
3335 return desiredAssertionStatus0(this);
3336 }
3337
3338 // Retrieves the desired assertion status of this class from the VM
3339 private static native boolean desiredAssertionStatus0(Class<?> clazz);
3340
3341 /**
3342 * Returns true if and only if this class was declared as an enum in the
3343 * source code.
3344 *
3345 * Note that {@link java.lang.Enum} is not itself an enum class.
3346 *
3347 * Also note that if an enum constant is declared with a class body,
3348 * the class of that enum constant object is an anonymous class
3349 * and <em>not</em> the class of the declaring enum class. The
3350 * {@link Enum#getDeclaringClass} method of an enum constant can
3351 * be used to get the class of the enum class declaring the
3352 * constant.
3353 *
3354 * @return true if and only if this class was declared as an enum in the
3355 * source code
3356 * @since 1.5
3357 * @jls 8.9.1 Enum Constants
3358 */
3359 public boolean isEnum() {
3360 // An enum must both directly extend java.lang.Enum and have
3361 // the ENUM bit set; classes for specialized enum constants
3362 // don't do the former.
3363 return (this.getModifiers() & ENUM) != 0 &&
3364 this.getSuperclass() == java.lang.Enum.class;
3365 }
3366
3367 /**
3368 * Returns {@code true} if and only if this class is a record class.
3369 *
3370 * <p> The {@linkplain #getSuperclass() direct superclass} of a record
3371 * class is {@code java.lang.Record}. A record class is {@linkplain
3372 * Modifier#FINAL final}. A record class has (possibly zero) record
3373 * components; {@link #getRecordComponents()} returns a non-null but
3374 * possibly empty value for a record.
3375 *
3376 * <p> Note that class {@link Record} is not a record class and thus
3377 * invoking this method on class {@code Record} returns {@code false}.
3378 *
3379 * @return true if and only if this class is a record class, otherwise false
3380 * @jls 8.10 Record Classes
3381 * @since 16
3382 */
3383 public boolean isRecord() {
3384 // this superclass and final modifier check is not strictly necessary
3385 // they are intrinsified and serve as a fast-path check
3386 return getSuperclass() == java.lang.Record.class &&
3387 (this.getModifiers() & Modifier.FINAL) != 0 &&
3388 isRecord0();
3389 }
3390
3391 // Fetches the factory for reflective objects
3392 private static ReflectionFactory getReflectionFactory() {
3393 var factory = reflectionFactory;
3394 if (factory != null) {
3395 return factory;
3396 }
3397 return reflectionFactory = ReflectionFactory.getReflectionFactory();
3398 }
3399 private static ReflectionFactory reflectionFactory;
3400
3401 /**
3402 * When CDS is enabled, the Class class may be aot-initialized. However,
3403 * we can't archive reflectionFactory, so we reset it to null, so it
3404 * will be allocated again at runtime.
3405 */
3406 private static void resetArchivedStates() {
3407 reflectionFactory = null;
3408 }
3409
3410 /**
3411 * Returns the elements of this enum class or null if this
3412 * Class object does not represent an enum class.
3413 *
3414 * @return an array containing the values comprising the enum class
3415 * represented by this {@code Class} object in the order they're
3416 * declared, or null if this {@code Class} object does not
3417 * represent an enum class
3418 * @since 1.5
3419 * @jls 8.9.1 Enum Constants
3420 */
3421 public T[] getEnumConstants() {
3422 T[] values = getEnumConstantsShared();
3423 return (values != null) ? values.clone() : null;
3424 }
3425
3426 /**
3427 * Returns the elements of this enum class or null if this
3428 * Class object does not represent an enum class;
3429 * identical to getEnumConstants except that the result is
3430 * uncloned, cached, and shared by all callers.
3431 */
3432 T[] getEnumConstantsShared() {
3433 T[] constants = enumConstants;
3434 if (constants == null) {
3435 if (!isEnum()) return null;
3436 try {
3437 final Method values = getMethod("values");
3438 values.setAccessible(true);
3439 @SuppressWarnings("unchecked")
3440 T[] temporaryConstants = (T[])values.invoke(null);
3441 enumConstants = constants = temporaryConstants;
3442 }
3443 // These can happen when users concoct enum-like classes
3444 // that don't comply with the enum spec.
3445 catch (InvocationTargetException | NoSuchMethodException |
3446 IllegalAccessException | NullPointerException |
3447 ClassCastException ex) { return null; }
3448 }
3449 return constants;
3450 }
3451 private transient volatile T[] enumConstants;
3452
3453 /**
3454 * Returns a map from simple name to enum constant. This package-private
3455 * method is used internally by Enum to implement
3456 * {@code public static <T extends Enum<T>> T valueOf(Class<T>, String)}
3457 * efficiently. Note that the map is returned by this method is
3458 * created lazily on first use. Typically it won't ever get created.
3459 */
3460 Map<String, T> enumConstantDirectory() {
3461 Map<String, T> directory = enumConstantDirectory;
3462 if (directory == null) {
3463 T[] universe = getEnumConstantsShared();
3464 if (universe == null)
3465 throw new IllegalArgumentException(
3466 getName() + " is not an enum class");
3467 directory = HashMap.newHashMap(universe.length);
3468 for (T constant : universe) {
3469 directory.put(((Enum<?>)constant).name(), constant);
3470 }
3471 enumConstantDirectory = directory;
3472 }
3473 return directory;
3474 }
3475 private transient volatile Map<String, T> enumConstantDirectory;
3476
3477 /**
3478 * Casts an object to the class or interface represented
3479 * by this {@code Class} object.
3480 *
3481 * @param obj the object to be cast, may be {@code null}
3482 * @return the object after casting, or null if obj is null
3483 *
3484 * @throws ClassCastException if the object is not
3485 * null and is not assignable to the type T.
3486 *
3487 * @since 1.5
3488 */
3489 @SuppressWarnings("unchecked")
3490 @IntrinsicCandidate
3491 public T cast(Object obj) {
3492 if (obj != null && !isInstance(obj))
3493 throw new ClassCastException(cannotCastMsg(obj));
3494 return (T) obj;
3495 }
3496
3497 private String cannotCastMsg(Object obj) {
3498 return "Cannot cast " + obj.getClass().getName() + " to " + getName();
3499 }
3500
3501 /**
3502 * Casts this {@code Class} object to represent a subclass of the class
3503 * represented by the specified class object. Checks that the cast
3504 * is valid, and throws a {@code ClassCastException} if it is not. If
3505 * this method succeeds, it always returns a reference to this {@code Class} object.
3506 *
3507 * <p>This method is useful when a client needs to "narrow" the type of
3508 * a {@code Class} object to pass it to an API that restricts the
3509 * {@code Class} objects that it is willing to accept. A cast would
3510 * generate a compile-time warning, as the correctness of the cast
3511 * could not be checked at runtime (because generic types are implemented
3512 * by erasure).
3513 *
3514 * @param <U> the type to cast this {@code Class} object to
3515 * @param clazz the class of the type to cast this {@code Class} object to
3516 * @return this {@code Class} object, cast to represent a subclass of
3517 * the specified class object.
3518 * @throws ClassCastException if this {@code Class} object does not
3519 * represent a subclass of the specified class (here "subclass" includes
3520 * the class itself).
3521 * @since 1.5
3522 */
3523 @SuppressWarnings("unchecked")
3524 public <U> Class<? extends U> asSubclass(Class<U> clazz) {
3525 if (clazz.isAssignableFrom(this))
3526 return (Class<? extends U>) this;
3527 else
3528 throw new ClassCastException(this.toString());
3529 }
3530
3531 /**
3532 * {@inheritDoc}
3533 * <p>Note that any annotation returned by this method is a
3534 * declaration annotation.
3535 *
3536 * @since 1.5
3537 */
3538 @Override
3539 @SuppressWarnings("unchecked")
3540 public <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
3541 Objects.requireNonNull(annotationClass);
3542
3543 return (A) annotationData().annotations.get(annotationClass);
3544 }
3545
3546 /**
3547 * {@inheritDoc}
3548 * @since 1.5
3549 */
3550 @Override
3551 public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {
3552 return GenericDeclaration.super.isAnnotationPresent(annotationClass);
3553 }
3554
3555 /**
3556 * {@inheritDoc}
3557 * <p>Note that any annotations returned by this method are
3558 * declaration annotations.
3559 *
3560 * @since 1.8
3561 */
3562 @Override
3563 public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationClass) {
3564 Objects.requireNonNull(annotationClass);
3565
3566 AnnotationData annotationData = annotationData();
3567 return AnnotationSupport.getAssociatedAnnotations(annotationData.declaredAnnotations,
3568 this,
3569 annotationClass);
3570 }
3571
3572 /**
3573 * {@inheritDoc}
3574 * <p>Note that any annotations returned by this method are
3575 * declaration annotations.
3576 *
3577 * @since 1.5
3578 */
3579 @Override
3580 public Annotation[] getAnnotations() {
3581 return AnnotationParser.toArray(annotationData().annotations);
3582 }
3583
3584 /**
3585 * {@inheritDoc}
3586 * <p>Note that any annotation returned by this method is a
3587 * declaration annotation.
3588 *
3589 * @since 1.8
3590 */
3591 @Override
3592 @SuppressWarnings("unchecked")
3593 public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationClass) {
3594 Objects.requireNonNull(annotationClass);
3595
3596 return (A) annotationData().declaredAnnotations.get(annotationClass);
3597 }
3598
3599 /**
3600 * {@inheritDoc}
3601 * <p>Note that any annotations returned by this method are
3602 * declaration annotations.
3603 *
3604 * @since 1.8
3605 */
3606 @Override
3607 public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationClass) {
3608 Objects.requireNonNull(annotationClass);
3609
3610 return AnnotationSupport.getDirectlyAndIndirectlyPresent(annotationData().declaredAnnotations,
3611 annotationClass);
3612 }
3613
3614 /**
3615 * {@inheritDoc}
3616 * <p>Note that any annotations returned by this method are
3617 * declaration annotations.
3618 *
3619 * @since 1.5
3620 */
3621 @Override
3622 public Annotation[] getDeclaredAnnotations() {
3623 return AnnotationParser.toArray(annotationData().declaredAnnotations);
3624 }
3625
3626 // annotation data that might get invalidated when JVM TI RedefineClasses() is called
3627 private static class AnnotationData {
3628 final Map<Class<? extends Annotation>, Annotation> annotations;
3629 final Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
3630
3631 // Value of classRedefinedCount when we created this AnnotationData instance
3632 final int redefinedCount;
3633
3634 AnnotationData(Map<Class<? extends Annotation>, Annotation> annotations,
3635 Map<Class<? extends Annotation>, Annotation> declaredAnnotations,
3636 int redefinedCount) {
3637 this.annotations = annotations;
3638 this.declaredAnnotations = declaredAnnotations;
3639 this.redefinedCount = redefinedCount;
3640 }
3641 }
3642
3643 // Annotations cache
3644 @SuppressWarnings("UnusedDeclaration")
3645 private transient volatile AnnotationData annotationData;
3646
3647 private AnnotationData annotationData() {
3648 while (true) { // retry loop
3649 AnnotationData annotationData = this.annotationData;
3650 int classRedefinedCount = this.classRedefinedCount;
3651 if (annotationData != null &&
3652 annotationData.redefinedCount == classRedefinedCount) {
3653 return annotationData;
3654 }
3655 // null or stale annotationData -> optimistically create new instance
3656 AnnotationData newAnnotationData = createAnnotationData(classRedefinedCount);
3657 // try to install it
3658 if (Atomic.casAnnotationData(this, annotationData, newAnnotationData)) {
3659 // successfully installed new AnnotationData
3660 return newAnnotationData;
3661 }
3662 }
3663 }
3664
3665 private AnnotationData createAnnotationData(int classRedefinedCount) {
3666 Map<Class<? extends Annotation>, Annotation> declaredAnnotations =
3667 AnnotationParser.parseAnnotations(getRawAnnotations(), getConstantPool(), this);
3668 Class<?> superClass = getSuperclass();
3669 Map<Class<? extends Annotation>, Annotation> annotations = null;
3670 if (superClass != null) {
3671 Map<Class<? extends Annotation>, Annotation> superAnnotations =
3672 superClass.annotationData().annotations;
3673 for (Map.Entry<Class<? extends Annotation>, Annotation> e : superAnnotations.entrySet()) {
3674 Class<? extends Annotation> annotationClass = e.getKey();
3675 if (AnnotationType.getInstance(annotationClass).isInherited()) {
3676 if (annotations == null) { // lazy construction
3677 annotations = LinkedHashMap.newLinkedHashMap(Math.max(
3678 declaredAnnotations.size(),
3679 Math.min(12, declaredAnnotations.size() + superAnnotations.size())
3680 )
3681 );
3682 }
3683 annotations.put(annotationClass, e.getValue());
3684 }
3685 }
3686 }
3687 if (annotations == null) {
3688 // no inherited annotations -> share the Map with declaredAnnotations
3689 annotations = declaredAnnotations;
3690 } else {
3691 // at least one inherited annotation -> declared may override inherited
3692 annotations.putAll(declaredAnnotations);
3693 }
3694 return new AnnotationData(annotations, declaredAnnotations, classRedefinedCount);
3695 }
3696
3697 // Annotation interfaces cache their internal (AnnotationType) form
3698
3699 @SuppressWarnings("UnusedDeclaration")
3700 private transient volatile AnnotationType annotationType;
3701
3702 boolean casAnnotationType(AnnotationType oldType, AnnotationType newType) {
3703 return Atomic.casAnnotationType(this, oldType, newType);
3704 }
3705
3706 AnnotationType getAnnotationType() {
3707 return annotationType;
3708 }
3709
3710 Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap() {
3711 return annotationData().declaredAnnotations;
3712 }
3713
3714 /* Backing store of user-defined values pertaining to this class.
3715 * Maintained by the ClassValue class.
3716 */
3717 transient ClassValue.ClassValueMap classValueMap;
3718
3719 /**
3720 * Returns an {@code AnnotatedType} object that represents the use of a
3721 * type to specify the superclass of the entity represented by this {@code
3722 * Class} object. (The <em>use</em> of type Foo to specify the superclass
3723 * in '... extends Foo' is distinct from the <em>declaration</em> of class
3724 * Foo.)
3725 *
3726 * <p> If this {@code Class} object represents a class whose declaration
3727 * does not explicitly indicate an annotated superclass, then the return
3728 * value is an {@code AnnotatedType} object representing an element with no
3729 * annotations.
3730 *
3731 * <p> If this {@code Class} represents either the {@code Object} class, an
3732 * interface type, an array type, a primitive type, or void, the return
3733 * value is {@code null}.
3734 *
3735 * @return an object representing the superclass
3736 * @since 1.8
3737 */
3738 public AnnotatedType getAnnotatedSuperclass() {
3739 if (this == Object.class ||
3740 isInterface() ||
3741 isArray() ||
3742 isPrimitive() ||
3743 this == Void.TYPE) {
3744 return null;
3745 }
3746
3747 return TypeAnnotationParser.buildAnnotatedSuperclass(getRawTypeAnnotations(), getConstantPool(), this);
3748 }
3749
3750 /**
3751 * Returns an array of {@code AnnotatedType} objects that represent the use
3752 * of types to specify superinterfaces of the entity represented by this
3753 * {@code Class} object. (The <em>use</em> of type Foo to specify a
3754 * superinterface in '... implements Foo' is distinct from the
3755 * <em>declaration</em> of interface Foo.)
3756 *
3757 * <p> If this {@code Class} object represents a class, the return value is
3758 * an array containing objects representing the uses of interface types to
3759 * specify interfaces implemented by the class. The order of the objects in
3760 * the array corresponds to the order of the interface types used in the
3761 * 'implements' clause of the declaration of this {@code Class} object.
3762 *
3763 * <p> If this {@code Class} object represents an interface, the return
3764 * value is an array containing objects representing the uses of interface
3765 * types to specify interfaces directly extended by the interface. The
3766 * order of the objects in the array corresponds to the order of the
3767 * interface types used in the 'extends' clause of the declaration of this
3768 * {@code Class} object.
3769 *
3770 * <p> If this {@code Class} object represents a class or interface whose
3771 * declaration does not explicitly indicate any annotated superinterfaces,
3772 * the return value is an array of length 0.
3773 *
3774 * <p> If this {@code Class} object represents either the {@code Object}
3775 * class, an array type, a primitive type, or void, the return value is an
3776 * array of length 0.
3777 *
3778 * @return an array representing the superinterfaces
3779 * @since 1.8
3780 */
3781 public AnnotatedType[] getAnnotatedInterfaces() {
3782 return TypeAnnotationParser.buildAnnotatedInterfaces(getRawTypeAnnotations(), getConstantPool(), this);
3783 }
3784
3785 private native Class<?> getNestHost0();
3786
3787 /**
3788 * Returns the nest host of the <a href=#nest>nest</a> to which the class
3789 * or interface represented by this {@code Class} object belongs.
3790 * Every class and interface belongs to exactly one nest.
3791 *
3792 * If the nest host of this class or interface has previously
3793 * been determined, then this method returns the nest host.
3794 * If the nest host of this class or interface has
3795 * not previously been determined, then this method determines the nest
3796 * host using the algorithm of JVMS 5.4.4, and returns it.
3797 *
3798 * Often, a class or interface belongs to a nest consisting only of itself,
3799 * in which case this method returns {@code this} to indicate that the class
3800 * or interface is the nest host.
3801 *
3802 * <p>If this {@code Class} object represents a primitive type, an array type,
3803 * or {@code void}, then this method returns {@code this},
3804 * indicating that the represented entity belongs to the nest consisting only of
3805 * itself, and is the nest host.
3806 *
3807 * @return the nest host of this class or interface
3808 *
3809 * @since 11
3810 * @jvms 4.7.28 The {@code NestHost} Attribute
3811 * @jvms 4.7.29 The {@code NestMembers} Attribute
3812 * @jvms 5.4.4 Access Control
3813 */
3814 public Class<?> getNestHost() {
3815 if (isPrimitive() || isArray()) {
3816 return this;
3817 }
3818 return getNestHost0();
3819 }
3820
3821 /**
3822 * Determines if the given {@code Class} is a nestmate of the
3823 * class or interface represented by this {@code Class} object.
3824 * Two classes or interfaces are nestmates
3825 * if they have the same {@linkplain #getNestHost() nest host}.
3826 *
3827 * @param c the class to check
3828 * @return {@code true} if this class and {@code c} are members of
3829 * the same nest; and {@code false} otherwise.
3830 *
3831 * @since 11
3832 */
3833 public boolean isNestmateOf(Class<?> c) {
3834 Objects.requireNonNull(c);
3835 if (this == c) {
3836 return true;
3837 }
3838 if (isPrimitive() || isArray() ||
3839 c.isPrimitive() || c.isArray()) {
3840 return false;
3841 }
3842
3843 return getNestHost() == c.getNestHost();
3844 }
3845
3846 private native Class<?>[] getNestMembers0();
3847
3848 /**
3849 * Returns an array containing {@code Class} objects representing all the
3850 * classes and interfaces that are members of the nest to which the class
3851 * or interface represented by this {@code Class} object belongs.
3852 *
3853 * First, this method obtains the {@linkplain #getNestHost() nest host},
3854 * {@code H}, of the nest to which the class or interface represented by
3855 * this {@code Class} object belongs. The zeroth element of the returned
3856 * array is {@code H}.
3857 *
3858 * Then, for each class or interface {@code C} which is recorded by {@code H}
3859 * as being a member of its nest, this method attempts to obtain the {@code Class}
3860 * object for {@code C} (using {@linkplain #getClassLoader() the defining class
3861 * loader} of the current {@code Class} object), and then obtains the
3862 * {@linkplain #getNestHost() nest host} of the nest to which {@code C} belongs.
3863 * The classes and interfaces which are recorded by {@code H} as being members
3864 * of its nest, and for which {@code H} can be determined as their nest host,
3865 * are indicated by subsequent elements of the returned array. The order of
3866 * such elements is unspecified. Duplicates are permitted.
3867 *
3868 * <p>If this {@code Class} object represents a primitive type, an array type,
3869 * or {@code void}, then this method returns a single-element array containing
3870 * {@code this}.
3871 *
3872 * @apiNote
3873 * The returned array includes only the nest members recorded in the {@code NestMembers}
3874 * attribute, and not any hidden classes that were added to the nest via
3875 * {@link MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
3876 * Lookup::defineHiddenClass}.
3877 *
3878 * @return an array of all classes and interfaces in the same nest as
3879 * this class or interface
3880 *
3881 * @since 11
3882 * @see #getNestHost()
3883 * @jvms 4.7.28 The {@code NestHost} Attribute
3884 * @jvms 4.7.29 The {@code NestMembers} Attribute
3885 */
3886 public Class<?>[] getNestMembers() {
3887 if (isPrimitive() || isArray()) {
3888 return new Class<?>[] { this };
3889 }
3890 Class<?>[] members = getNestMembers0();
3891 // Can't actually enable this due to bootstrapping issues
3892 // assert(members.length != 1 || members[0] == this); // expected invariant from VM
3893 return members;
3894 }
3895
3896 /**
3897 * Returns the descriptor string of the entity (class, interface, array class,
3898 * primitive type, or {@code void}) represented by this {@code Class} object.
3899 *
3900 * <p> If this {@code Class} object represents a class or interface,
3901 * not an array class, then:
3902 * <ul>
3903 * <li> If the class or interface is not {@linkplain Class#isHidden() hidden},
3904 * then the result is a field descriptor (JVMS {@jvms 4.3.2})
3905 * for the class or interface. Calling
3906 * {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}
3907 * with the result descriptor string produces a {@link ClassDesc ClassDesc}
3908 * describing this class or interface.
3909 * <li> If the class or interface is {@linkplain Class#isHidden() hidden},
3910 * then the result is a string of the form:
3911 * <blockquote>
3912 * {@code "L" +} <em>N</em> {@code + "." + <suffix> + ";"}
3913 * </blockquote>
3914 * where <em>N</em> is the {@linkplain ClassLoader##binary-name binary name}
3915 * encoded in internal form indicated by the {@code class} file passed to
3916 * {@link MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
3917 * Lookup::defineHiddenClass}, and {@code <suffix>} is an unqualified name.
3918 * A hidden class or interface has no {@linkplain ClassDesc nominal descriptor}.
3919 * The result string is not a type descriptor.
3920 * </ul>
3921 *
3922 * <p> If this {@code Class} object represents an array class, then
3923 * the result is a string consisting of one or more '{@code [}' characters
3924 * representing the depth of the array nesting, followed by the
3925 * descriptor string of the element type.
3926 * <ul>
3927 * <li> If the element type is not a {@linkplain Class#isHidden() hidden} class
3928 * or interface, then this array class can be described nominally.
3929 * Calling {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}
3930 * with the result descriptor string produces a {@link ClassDesc ClassDesc}
3931 * describing this array class.
3932 * <li> If the element type is a {@linkplain Class#isHidden() hidden} class or
3933 * interface, then this array class cannot be described nominally.
3934 * The result string is not a type descriptor.
3935 * </ul>
3936 *
3937 * <p> If this {@code Class} object represents a primitive type or
3938 * {@code void}, then the result is a field descriptor string which
3939 * is a one-letter code corresponding to a primitive type or {@code void}
3940 * ({@code "B", "C", "D", "F", "I", "J", "S", "Z", "V"}) (JVMS {@jvms 4.3.2}).
3941 *
3942 * @return the descriptor string for this {@code Class} object
3943 * @jvms 4.3.2 Field Descriptors
3944 * @since 12
3945 */
3946 @Override
3947 public String descriptorString() {
3948 if (isPrimitive())
3949 return Wrapper.forPrimitiveType(this).basicTypeString();
3950
3951 if (isArray()) {
3952 return "[".concat(componentType.descriptorString());
3953 } else if (isHidden()) {
3954 String name = getName();
3955 int index = name.indexOf('/');
3956 return new StringBuilder(name.length() + 2)
3957 .append('L')
3958 .append(name.substring(0, index).replace('.', '/'))
3959 .append('.')
3960 .append(name, index + 1, name.length())
3961 .append(';')
3962 .toString();
3963 } else {
3964 String name = getName().replace('.', '/');
3965 return StringConcatHelper.concat("L", name, ";");
3966 }
3967 }
3968
3969 /**
3970 * Returns the component type of this {@code Class}, if it describes
3971 * an array type, or {@code null} otherwise.
3972 *
3973 * @implSpec
3974 * Equivalent to {@link Class#getComponentType()}.
3975 *
3976 * @return a {@code Class} describing the component type, or {@code null}
3977 * if this {@code Class} does not describe an array type
3978 * @since 12
3979 */
3980 @Override
3981 public Class<?> componentType() {
3982 return getComponentType();
3983 }
3984
3985 /**
3986 * Returns a {@code Class} for an array type whose component type
3987 * is described by this {@linkplain Class}.
3988 *
3989 * @throws UnsupportedOperationException if this component type is {@linkplain
3990 * Void#TYPE void} or if the number of dimensions of the resulting array
3991 * type would exceed 255.
3992 * @return a {@code Class} describing the array type
3993 * @jvms 4.3.2 Field Descriptors
3994 * @jvms 4.4.1 The {@code CONSTANT_Class_info} Structure
3995 * @since 12
3996 */
3997 @Override
3998 public Class<?> arrayType() {
3999 try {
4000 return Array.newInstance(this, 0).getClass();
4001 } catch (IllegalArgumentException iae) {
4002 throw new UnsupportedOperationException(iae);
4003 }
4004 }
4005
4006 /**
4007 * Returns a nominal descriptor for this instance, if one can be
4008 * constructed, or an empty {@link Optional} if one cannot be.
4009 *
4010 * @return An {@link Optional} containing the resulting nominal descriptor,
4011 * or an empty {@link Optional} if one cannot be constructed.
4012 * @since 12
4013 */
4014 @Override
4015 public Optional<ClassDesc> describeConstable() {
4016 Class<?> c = isArray() ? elementType() : this;
4017 return c.isHidden() ? Optional.empty()
4018 : Optional.of(ConstantUtils.classDesc(this));
4019 }
4020
4021 /**
4022 * Returns {@code true} if and only if the underlying class is a hidden class.
4023 *
4024 * @return {@code true} if and only if this class is a hidden class.
4025 *
4026 * @since 15
4027 * @see MethodHandles.Lookup#defineHiddenClass
4028 * @see Class##hiddenClasses Hidden Classes
4029 */
4030 @IntrinsicCandidate
4031 public native boolean isHidden();
4032
4033 /**
4034 * Returns an array containing {@code Class} objects representing the
4035 * direct subinterfaces or subclasses permitted to extend or
4036 * implement this class or interface if it is sealed. The order of such elements
4037 * is unspecified. The array is empty if this sealed class or interface has no
4038 * permitted subclass. If this {@code Class} object represents a primitive type,
4039 * {@code void}, an array type, or a class or interface that is not sealed,
4040 * that is {@link #isSealed()} returns {@code false}, then this method returns {@code null}.
4041 * Conversely, if {@link #isSealed()} returns {@code true}, then this method
4042 * returns a non-null value.
4043 *
4044 * For each class or interface {@code C} which is recorded as a permitted
4045 * direct subinterface or subclass of this class or interface,
4046 * this method attempts to obtain the {@code Class}
4047 * object for {@code C} (using {@linkplain #getClassLoader() the defining class
4048 * loader} of the current {@code Class} object).
4049 * The {@code Class} objects which can be obtained and which are direct
4050 * subinterfaces or subclasses of this class or interface,
4051 * are indicated by elements of the returned array. If a {@code Class} object
4052 * cannot be obtained, it is silently ignored, and not included in the result
4053 * array.
4054 *
4055 * @return an array of {@code Class} objects of the permitted subclasses of this class
4056 * or interface, or {@code null} if this class or interface is not sealed.
4057 *
4058 * @jls 8.1 Class Declarations
4059 * @jls 9.1 Interface Declarations
4060 * @since 17
4061 */
4062 public Class<?>[] getPermittedSubclasses() {
4063 Class<?>[] subClasses;
4064 if (isArray() || isPrimitive() || (subClasses = getPermittedSubclasses0()) == null) {
4065 return null;
4066 }
4067 if (subClasses.length > 0) {
4068 if (Arrays.stream(subClasses).anyMatch(c -> !isDirectSubType(c))) {
4069 subClasses = Arrays.stream(subClasses)
4070 .filter(this::isDirectSubType)
4071 .toArray(s -> new Class<?>[s]);
4072 }
4073 }
4074 return subClasses;
4075 }
4076
4077 private boolean isDirectSubType(Class<?> c) {
4078 if (isInterface()) {
4079 for (Class<?> i : c.getInterfaces(/* cloneArray */ false)) {
4080 if (i == this) {
4081 return true;
4082 }
4083 }
4084 } else {
4085 return c.getSuperclass() == this;
4086 }
4087 return false;
4088 }
4089
4090 /**
4091 * Returns {@code true} if and only if this {@code Class} object represents
4092 * a sealed class or interface. If this {@code Class} object represents a
4093 * primitive type, {@code void}, or an array type, this method returns
4094 * {@code false}. A sealed class or interface has (possibly zero) permitted
4095 * subclasses; {@link #getPermittedSubclasses()} returns a non-null but
4096 * possibly empty value for a sealed class or interface.
4097 *
4098 * @return {@code true} if and only if this {@code Class} object represents
4099 * a sealed class or interface.
4100 *
4101 * @jls 8.1 Class Declarations
4102 * @jls 9.1 Interface Declarations
4103 * @since 17
4104 */
4105 public boolean isSealed() {
4106 if (isArray() || isPrimitive()) {
4107 return false;
4108 }
4109 return getPermittedSubclasses() != null;
4110 }
4111
4112 private native Class<?>[] getPermittedSubclasses0();
4113
4114 /*
4115 * Return the class's major and minor class file version packed into an int.
4116 * The high order 16 bits contain the class's minor version. The low order
4117 * 16 bits contain the class's major version.
4118 *
4119 * If the class is an array type then the class file version of its element
4120 * type is returned. If the class is a primitive type then the latest class
4121 * file major version is returned and zero is returned for the minor version.
4122 */
4123 int getClassFileVersion() {
4124 Class<?> c = isArray() ? elementType() : this;
4125 return c.getClassFileVersion0();
4126 }
4127
4128 private native int getClassFileVersion0();
4129
4130 /**
4131 * Return the access flags as they were in the class's bytecode, including
4132 * the original setting of ACC_SUPER.
4133 *
4134 * If this {@code Class} object represents a primitive type or
4135 * void, the flags are {@code PUBLIC}, {@code ABSTRACT}, and
4136 * {@code FINAL}.
4137 * If this {@code Class} object represents an array type, return 0.
4138 */
4139 int getClassFileAccessFlags() {
4140 return classFileAccessFlags;
4141 }
4142
4143 // Validates the length of the class name and throws an exception if it exceeds the maximum allowed length.
4144 private static void validateClassNameLength(String name) throws ClassNotFoundException {
4145 if (!ModifiedUtf.isValidLengthInConstantPool(name)) {
4146 throw new ClassNotFoundException(
4147 "Class name length exceeds limit of "
4148 + ModifiedUtf.CONSTANT_POOL_UTF8_MAX_BYTES
4149 + ": " + name.substring(0,256) + "...");
4150 }
4151 }
4152 }