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