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