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.Proxy;
51 import java.lang.reflect.RecordComponent;
52 import java.lang.reflect.Type;
53 import java.lang.reflect.TypeVariable;
54 import java.lang.constant.Constable;
55 import java.net.URL;
56 import java.security.AllPermission;
57 import java.security.Permissions;
58 import java.security.ProtectionDomain;
59 import java.util.ArrayList;
60 import java.util.Arrays;
61 import java.util.Collection;
62 import java.util.HashMap;
63 import java.util.LinkedHashMap;
64 import java.util.LinkedHashSet;
65 import java.util.List;
66 import java.util.Map;
67 import java.util.Objects;
68 import java.util.Optional;
69 import java.util.Set;
70 import java.util.stream.Collectors;
71
72 import jdk.internal.constant.ConstantUtils;
73 import jdk.internal.loader.BootLoader;
74 import jdk.internal.loader.BuiltinClassLoader;
75 import jdk.internal.misc.Unsafe;
76 import jdk.internal.module.Resources;
77 import jdk.internal.reflect.CallerSensitive;
78 import jdk.internal.reflect.CallerSensitiveAdapter;
79 import jdk.internal.reflect.ConstantPool;
80 import jdk.internal.reflect.Reflection;
81 import jdk.internal.reflect.ReflectionFactory;
82 import jdk.internal.vm.annotation.IntrinsicCandidate;
83 import jdk.internal.vm.annotation.Stable;
84
85 import sun.invoke.util.Wrapper;
86 import sun.reflect.generics.factory.CoreReflectionFactory;
87 import sun.reflect.generics.factory.GenericsFactory;
88 import sun.reflect.generics.repository.ClassRepository;
89 import sun.reflect.generics.repository.MethodRepository;
90 import sun.reflect.generics.repository.ConstructorRepository;
91 import sun.reflect.generics.scope.ClassScope;
92 import sun.reflect.annotation.*;
93
94 /**
95 * Instances of the class {@code Class} represent classes and
96 * interfaces in a running Java application. An enum class and a record
97 * class are kinds of class; an annotation interface is a kind of
98 * interface. Every array also belongs to a class that is reflected as
99 * a {@code Class} object that is shared by all arrays with the same
100 * element type and number of dimensions. The primitive Java types
101 * ({@code boolean}, {@code byte}, {@code char}, {@code short}, {@code
102 * int}, {@code long}, {@code float}, and {@code double}), and the
103 * keyword {@code void} are also represented as {@code Class} objects.
104 *
105 * <p> {@code Class} has no public constructor. Instead a {@code Class}
106 * object is constructed automatically by the Java Virtual Machine when
107 * a class is derived from the bytes of a {@code class} file through
108 * the invocation of one of the following methods:
109 * <ul>
110 * <li> {@link ClassLoader#defineClass(String, byte[], int, int) ClassLoader::defineClass}
111 * <li> {@link java.lang.invoke.MethodHandles.Lookup#defineClass(byte[])
112 * java.lang.invoke.MethodHandles.Lookup::defineClass}
113 * <li> {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
114 * java.lang.invoke.MethodHandles.Lookup::defineHiddenClass}
115 * </ul>
116 *
117 * <p> The methods of class {@code Class} expose many characteristics of a
118 * class or interface. Most characteristics are derived from the {@code class}
119 * file that the class loader passed to the Java Virtual Machine or
120 * from the {@code class} file passed to {@code Lookup::defineClass}
121 * or {@code Lookup::defineHiddenClass}.
122 * A few characteristics are determined by the class loading environment
123 * at run time, such as the module returned by {@link #getModule() getModule()}.
124 *
125 * <p> The following example uses a {@code Class} object to print the
126 * class name of an object:
127 *
128 * {@snippet lang="java" :
129 * void printClassName(Object obj) {
130 * System.out.println("The class of " + obj +
131 * " is " + obj.getClass().getName());
132 * }}
133 *
134 * It is also possible to get the {@code Class} object for a named
135 * class or interface (or for {@code void}) using a <dfn>class literal</dfn>
136 * (JLS {@jls 15.8.2}).
137 * For example:
138 *
139 * {@snippet lang="java" :
140 * System.out.println("The name of class Foo is: " + Foo.class.getName()); // @highlight substring="Foo.class"
141 * }
142 *
143 * <p> Some methods of class {@code Class} expose whether the declaration of
144 * a class or interface in Java source code was <em>enclosed</em> within
145 * another declaration. Other methods describe how a class or interface
146 * is situated in a <dfn>{@index "nest"}</dfn>. A nest is a set of
147 * classes and interfaces, in the same run-time package, that
148 * allow mutual access to their {@code private} members.
149 * The classes and interfaces are known as <dfn>{@index "nestmates"}</dfn>
150 * (JVMS {@jvms 4.7.29}).
151 * One nestmate acts as the
152 * <dfn>nest host</dfn> (JVMS {@jvms 4.7.28}), and enumerates the other nestmates which
153 * belong to the nest; each of them in turn records it as the nest host.
154 * The classes and interfaces which belong to a nest, including its host, are
155 * determined when
156 * {@code class} files are generated, for example, a Java compiler
157 * will typically record a top-level class as the host of a nest where the
158 * other members are the classes and interfaces whose declarations are
159 * enclosed within the top-level class declaration.
160 *
161 * <h2><a id=hiddenClasses>Hidden Classes</a></h2>
162 * A class or interface created by the invocation of
163 * {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
164 * Lookup::defineHiddenClass} is a {@linkplain Class#isHidden() <dfn>hidden</dfn>}
165 * class or interface.
166 * All kinds of class, including enum classes and record classes, may be
167 * hidden classes; all kinds of interface, including annotation interfaces,
168 * may be hidden interfaces.
169 *
170 * The {@linkplain #getName() name of a hidden class or interface} is
171 * not a {@linkplain ClassLoader##binary-name binary name},
172 * which means the following:
173 * <ul>
174 * <li>A hidden class or interface cannot be referenced by the constant pools
175 * of other classes and interfaces.
176 * <li>A hidden class or interface cannot be described in
177 * {@linkplain java.lang.constant.ConstantDesc <em>nominal form</em>} by
178 * {@link #describeConstable() Class::describeConstable},
179 * {@link ClassDesc#of(String) ClassDesc::of}, or
180 * {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}.
181 * <li>A hidden class or interface cannot be discovered by {@link #forName Class::forName}
182 * or {@link ClassLoader#loadClass(String, boolean) ClassLoader::loadClass}.
183 * </ul>
184 *
185 * A hidden class or interface is never an array class, but may be
186 * the element type of an array. In all other respects, the fact that
187 * a class or interface is hidden has no bearing on the characteristics
188 * exposed by the methods of class {@code Class}.
189 *
190 * <h2><a id=implicitClasses>Implicitly Declared Classes</a></h2>
191 *
192 * Conventionally, a Java compiler, starting from a source file for an
193 * implicitly declared class, say {@code HelloWorld.java}, creates a
194 * similarly-named {@code class} file, {@code HelloWorld.class}, where
195 * the class stored in that {@code class} file is named {@code
196 * "HelloWorld"}, matching the base names of the source and {@code
197 * class} files.
198 *
199 * For the {@code Class} object of an implicitly declared class {@code
200 * HelloWorld}, the methods to get the {@linkplain #getName name} and
201 * {@linkplain #getTypeName type name} return results
202 * equal to {@code "HelloWorld"}. The {@linkplain #getSimpleName
203 * simple name} of such an implicitly declared class is {@code "HelloWorld"} and
204 * the {@linkplain #getCanonicalName canonical name} is {@code "HelloWorld"}.
205 *
206 * @param <T> the type of the class modeled by this {@code Class}
207 * object. For example, the type of {@code String.class} is {@code
208 * Class<String>}. Use {@code Class<?>} if the class being modeled is
209 * unknown.
210 *
211 * @see java.lang.ClassLoader#defineClass(byte[], int, int)
212 * @since 1.0
213 */
214 public final class Class<T> implements java.io.Serializable,
215 GenericDeclaration,
216 Type,
217 AnnotatedElement,
218 TypeDescriptor.OfField<Class<?>>,
219 Constable {
220 private static final int ANNOTATION= 0x00002000;
221 private static final int ENUM = 0x00004000;
222 private static final int SYNTHETIC = 0x00001000;
223
224 private static native void registerNatives();
225 static {
226 runtimeSetup();
227 }
228
229 // Called from JVM when loading an AOT cache
230 private static void runtimeSetup() {
231 registerNatives();
232 }
233
234 /*
235 * Private constructor. Only the Java Virtual Machine creates Class objects.
236 * This constructor is not used and prevents the default constructor being
237 * generated.
238 */
239 private Class(ClassLoader loader, Class<?> arrayComponentType, char mods, ProtectionDomain pd, boolean isPrim) {
240 // Initialize final field for classLoader. The initialization value of non-null
241 // prevents future JIT optimizations from assuming this final field is null.
242 // The following assignments are done directly by the VM without calling this constructor.
243 classLoader = loader;
244 componentType = arrayComponentType;
245 modifiers = mods;
246 protectionDomain = pd;
247 primitive = isPrim;
248 }
249
250 /**
251 * Converts the object to a string. The string representation is the
252 * string "class" or "interface", followed by a space, and then by the
253 * name of the class in the format returned by {@code getName}.
254 * If this {@code Class} object represents a primitive type,
255 * this method returns the name of the primitive type. If
256 * this {@code Class} object represents void this method returns
257 * "void". If this {@code Class} object represents an array type,
258 * this method returns "class " followed by {@code getName}.
259 *
260 * @return a string representation of this {@code Class} object.
261 */
262 public String toString() {
263 String kind = isInterface() ? "interface " : isPrimitive() ? "" : "class ";
264 return kind.concat(getName());
265 }
266
267 /**
268 * Returns a string describing this {@code Class}, including
269 * information about modifiers, {@link #isSealed() sealed}/{@code
270 * non-sealed} status, and type parameters.
271 *
272 * The string is formatted as a list of type modifiers, if any,
273 * followed by the kind of type (empty string for primitive types
274 * and {@code class}, {@code enum}, {@code interface},
275 * {@code @interface}, or {@code record} as appropriate), followed
276 * by the type's name, followed by an angle-bracketed
277 * comma-separated list of the type's type parameters, if any,
278 * including informative bounds on the type parameters, if any.
279 *
280 * A space is used to separate modifiers from one another and to
281 * separate any modifiers from the kind of type. The modifiers
282 * occur in canonical order. If there are no type parameters, the
283 * type parameter list is elided.
284 *
285 * For an array type, the string starts with the type name,
286 * followed by an angle-bracketed comma-separated list of the
287 * type's type parameters, if any, followed by a sequence of
288 * {@code []} characters, one set of brackets per dimension of
289 * the array.
290 *
291 * <p>Note that since information about the runtime representation
292 * of a type is being generated, modifiers not present on the
293 * originating source code or illegal on the originating source
294 * code may be present.
295 *
296 * @return a string describing this {@code Class}, including
297 * information about modifiers and type parameters
298 *
299 * @since 1.8
300 */
301 public String toGenericString() {
302 if (isPrimitive()) {
303 return toString();
304 } else {
305 StringBuilder sb = new StringBuilder();
306 Class<?> component = this;
307 int arrayDepth = 0;
308
309 if (isArray()) {
310 do {
311 arrayDepth++;
312 component = component.getComponentType();
313 } while (component.isArray());
314 sb.append(component.getName());
315 } else {
316 // Class modifiers are a superset of interface modifiers
317 int modifiers = getModifiers() & Modifier.classModifiers();
318 if (modifiers != 0) {
319 sb.append(Modifier.toString(modifiers));
320 sb.append(' ');
321 }
322
323 // A class cannot be strictfp and sealed/non-sealed so
324 // it is sufficient to check for sealed-ness after all
325 // modifiers are printed.
326 addSealingInfo(modifiers, sb);
327
328 if (isAnnotation()) {
329 sb.append('@');
330 }
331 if (isInterface()) { // Note: all annotation interfaces are interfaces
332 sb.append("interface");
333 } else {
334 if (isEnum())
335 sb.append("enum");
336 else if (isRecord())
337 sb.append("record");
338 else
339 sb.append("class");
340 }
341 sb.append(' ');
342 sb.append(getName());
343 }
344
345 TypeVariable<?>[] typeparms = component.getTypeParameters();
346 if (typeparms.length > 0) {
347 sb.append(Arrays.stream(typeparms)
348 .map(Class::typeVarBounds)
349 .collect(Collectors.joining(",", "<", ">")));
350 }
351
352 if (arrayDepth > 0) sb.append("[]".repeat(arrayDepth));
353
354 return sb.toString();
355 }
356 }
357
358 private void addSealingInfo(int modifiers, StringBuilder sb) {
359 // A class can be final XOR sealed XOR non-sealed.
360 if (Modifier.isFinal(modifiers)) {
361 return; // no-op
362 } else {
363 if (isSealed()) {
364 sb.append("sealed ");
365 return;
366 } else {
367 // Check for sealed ancestor, which implies this class
368 // is non-sealed.
369 if (hasSealedAncestor(this)) {
370 sb.append("non-sealed ");
371 }
372 }
373 }
374 }
375
376 private boolean hasSealedAncestor(Class<?> clazz) {
377 // From JLS 8.1.1.2:
378 // "It is a compile-time error if a class has a sealed direct
379 // superclass or a sealed direct superinterface, and is not
380 // declared final, sealed, or non-sealed either explicitly or
381 // implicitly.
382 // Thus, an effect of the sealed keyword is to force all
383 // direct subclasses to explicitly declare whether they are
384 // final, sealed, or non-sealed. This avoids accidentally
385 // exposing a sealed class hierarchy to unwanted subclassing."
386
387 // Therefore, will just check direct superclass and
388 // superinterfaces.
389 var superclass = clazz.getSuperclass();
390 if (superclass != null && superclass.isSealed()) {
391 return true;
392 }
393 for (var superinterface : clazz.getInterfaces()) {
394 if (superinterface.isSealed()) {
395 return true;
396 }
397 }
398 return false;
399 }
400
401 static String typeVarBounds(TypeVariable<?> typeVar) {
402 Type[] bounds = typeVar.getBounds();
403 if (bounds.length == 1 && bounds[0].equals(Object.class)) {
404 return typeVar.getName();
405 } else {
406 return typeVar.getName() + " extends " +
407 Arrays.stream(bounds)
408 .map(Type::getTypeName)
409 .collect(Collectors.joining(" & "));
410 }
411 }
412
413 /**
414 * Returns the {@code Class} object associated with the class or
415 * interface with the given string name. Invoking this method is
416 * equivalent to:
417 *
418 * {@snippet lang="java" :
419 * Class.forName(className, true, currentLoader)
420 * }
421 *
422 * where {@code currentLoader} denotes the defining class loader of
423 * the current class.
424 *
425 * <p> For example, the following code fragment returns the
426 * runtime {@code Class} object for the class named
427 * {@code java.lang.Thread}:
428 *
429 * {@snippet lang="java" :
430 * Class<?> t = Class.forName("java.lang.Thread");
431 * }
432 * <p>
433 * A call to {@code forName("X")} causes the class named
434 * {@code X} to be initialized.
435 *
436 * <p>
437 * In cases where this method is called from a context where there is no
438 * caller frame on the stack (e.g. when called directly from a JNI
439 * attached thread), the system class loader is used.
440 *
441 * @param className the {@linkplain ClassLoader##binary-name binary name}
442 * of the class or the string representing an array type
443 * @return the {@code Class} object for the class with the
444 * specified name.
445 * @throws LinkageError if the linkage fails
446 * @throws ExceptionInInitializerError if the initialization provoked
447 * by this method fails
448 * @throws ClassNotFoundException if the class cannot be located
449 *
450 * @jls 12.2 Loading of Classes and Interfaces
451 * @jls 12.3 Linking of Classes and Interfaces
452 * @jls 12.4 Initialization of Classes and Interfaces
453 */
454 @CallerSensitive
455 public static Class<?> forName(String className)
456 throws ClassNotFoundException {
457 Class<?> caller = Reflection.getCallerClass();
458 return forName(className, caller);
459 }
460
461 // Caller-sensitive adapter method for reflective invocation
462 @CallerSensitiveAdapter
463 private static Class<?> forName(String className, Class<?> caller)
464 throws ClassNotFoundException {
465 ClassLoader loader = (caller == null) ? ClassLoader.getSystemClassLoader()
466 : ClassLoader.getClassLoader(caller);
467 return forName0(className, true, loader, caller);
468 }
469
470 /**
471 * Returns the {@code Class} object associated with the class or
472 * interface with the given string name, using the given class loader.
473 * Given the {@linkplain ClassLoader##binary-name binary name} for a class or interface,
474 * this method attempts to locate and load the class or interface. The specified
475 * class loader is used to load the class or interface. If the parameter
476 * {@code loader} is {@code null}, the class is loaded through the bootstrap
477 * class loader. The class is initialized only if the
478 * {@code initialize} parameter is {@code true} and if it has
479 * not been initialized earlier.
480 *
481 * <p> This method cannot be used to obtain any of the {@code Class} objects
482 * representing primitive types or void, hidden classes or interfaces,
483 * or array classes whose element type is a hidden class or interface.
484 * If {@code name} denotes a primitive type or void, for example {@code I},
485 * an attempt will be made to locate a user-defined class in the unnamed package
486 * whose name is {@code I} instead.
487 * To obtain a {@code Class} object for a named primitive type
488 * such as {@code int} or {@code long} use {@link
489 * #forPrimitiveName(String)}.
490 *
491 * <p> To obtain the {@code Class} object associated with an array class,
492 * the name consists of one or more {@code '['} representing the depth
493 * of the array nesting, followed by the element type as encoded in
494 * {@linkplain ##nameFormat the table} specified in {@code Class.getName()}.
495 *
496 * <p> Examples:
497 * {@snippet lang="java" :
498 * Class<?> threadClass = Class.forName("java.lang.Thread", false, currentLoader);
499 * Class<?> stringArrayClass = Class.forName("[Ljava.lang.String;", false, currentLoader);
500 * Class<?> intArrayClass = Class.forName("[[[I", false, currentLoader); // Class of int[][][]
501 * Class<?> nestedClass = Class.forName("java.lang.Character$UnicodeBlock", false, currentLoader);
502 * Class<?> fooClass = Class.forName("Foo", true, currentLoader);
503 * }
504 *
505 * <p> A call to {@code getName()} on the {@code Class} object returned
506 * from {@code forName(}<i>N</i>{@code )} returns <i>N</i>.
507 *
508 * <p> A call to {@code forName("[L}<i>N</i>{@code ;")} causes the element type
509 * named <i>N</i> to be loaded but not initialized regardless of the value
510 * of the {@code initialize} parameter.
511 *
512 * @apiNote
513 * This method throws errors related to loading, linking or initializing
514 * as specified in Sections {@jls 12.2}, {@jls 12.3}, and {@jls 12.4} of
515 * <cite>The Java Language Specification</cite>.
516 * In addition, this method does not check whether the requested class
517 * is accessible to its caller.
518 *
519 * @param name the {@linkplain ClassLoader##binary-name binary name}
520 * of the class or the string representing an array class
521 *
522 * @param initialize if {@code true} the class will be initialized
523 * (which implies linking). See Section {@jls
524 * 12.4} of <cite>The Java Language
525 * Specification</cite>.
526 * @param loader class loader from which the class must be loaded
527 * @return class object representing the desired class
528 *
529 * @throws LinkageError if the linkage fails
530 * @throws ExceptionInInitializerError if the initialization provoked
531 * by this method fails
532 * @throws ClassNotFoundException if the class cannot be located by
533 * the specified class loader
534 *
535 * @see java.lang.Class#forName(String)
536 * @see java.lang.ClassLoader
537 *
538 * @jls 12.2 Loading of Classes and Interfaces
539 * @jls 12.3 Linking of Classes and Interfaces
540 * @jls 12.4 Initialization of Classes and Interfaces
541 * @jls 13.1 The Form of a Binary
542 * @since 1.2
543 */
544 public static Class<?> forName(String name, boolean initialize, ClassLoader loader)
545 throws ClassNotFoundException
546 {
547 return forName0(name, initialize, loader, null);
548 }
549
550 /** Called after security check for system loader access checks have been made. */
551 private static native Class<?> forName0(String name, boolean initialize,
552 ClassLoader loader,
553 Class<?> caller)
554 throws ClassNotFoundException;
555
556
557 /**
558 * Returns the {@code Class} with the given {@linkplain ClassLoader##binary-name
559 * binary name} in the given module.
560 *
561 * <p> This method attempts to locate and load the class or interface.
562 * It does not link the class, and does not run the class initializer.
563 * If the class is not found, this method returns {@code null}. </p>
564 *
565 * <p> If the class loader of the given module defines other modules and
566 * the given name is a class defined in a different module, this method
567 * returns {@code null} after the class is loaded. </p>
568 *
569 * <p> This method does not check whether the requested class is
570 * accessible to its caller. </p>
571 *
572 * @apiNote
573 * This method does not support loading of array types, unlike
574 * {@link #forName(String, boolean, ClassLoader)}. The class name must be
575 * a binary name. This method returns {@code null} on failure rather than
576 * throwing a {@link ClassNotFoundException}, as is done by
577 * the {@link #forName(String, boolean, ClassLoader)} method.
578 *
579 * @param module A module
580 * @param name The {@linkplain ClassLoader##binary-name binary name}
581 * of the class
582 * @return {@code Class} object of the given name defined in the given module;
583 * {@code null} if not found.
584 *
585 * @throws NullPointerException if the given module or name is {@code null}
586 *
587 * @throws LinkageError if the linkage fails
588 *
589 * @jls 12.2 Loading of Classes and Interfaces
590 * @jls 12.3 Linking of Classes and Interfaces
591 * @since 9
592 */
593 public static Class<?> forName(Module module, String name) {
594 Objects.requireNonNull(module);
595 Objects.requireNonNull(name);
596
597 ClassLoader cl = module.getClassLoader();
598 if (cl != null) {
599 return cl.loadClass(module, name);
600 } else {
601 return BootLoader.loadClass(module, name);
602 }
603 }
604
605 /**
606 * {@return the {@code Class} object associated with the
607 * {@linkplain #isPrimitive() primitive type} of the given name}
608 * If the argument is not the name of a primitive type, {@code
609 * null} is returned.
610 *
611 * @param primitiveName the name of the primitive type to find
612 *
613 * @throws NullPointerException if the argument is {@code null}
614 *
615 * @jls 4.2 Primitive Types and Values
616 * @jls 15.8.2 Class Literals
617 * @since 22
618 */
619 public static Class<?> forPrimitiveName(String primitiveName) {
620 return switch(primitiveName) {
621 // Integral types
622 case "int" -> int.class;
623 case "long" -> long.class;
624 case "short" -> short.class;
625 case "char" -> char.class;
626 case "byte" -> byte.class;
627
628 // Floating-point types
629 case "float" -> float.class;
630 case "double" -> double.class;
631
632 // Other types
633 case "boolean" -> boolean.class;
634 case "void" -> void.class;
635
636 default -> null;
637 };
638 }
639
640 /**
641 * Creates a new instance of the class represented by this {@code Class}
642 * object. The class is instantiated as if by a {@code new}
643 * expression with an empty argument list. The class is initialized if it
644 * has not already been initialized.
645 *
646 * @deprecated This method propagates any exception thrown by the
647 * nullary constructor, including a checked exception. Use of
648 * this method effectively bypasses the compile-time exception
649 * checking that would otherwise be performed by the compiler.
650 * The {@link
651 * java.lang.reflect.Constructor#newInstance(java.lang.Object...)
652 * Constructor.newInstance} method avoids this problem by wrapping
653 * any exception thrown by the constructor in a (checked) {@link
654 * java.lang.reflect.InvocationTargetException}.
655 *
656 * <p>The call
657 *
658 * {@snippet lang="java" :
659 * clazz.newInstance()
660 * }
661 *
662 * can be replaced by
663 *
664 * {@snippet lang="java" :
665 * clazz.getDeclaredConstructor().newInstance()
666 * }
667 *
668 * The latter sequence of calls is inferred to be able to throw
669 * the additional exception types {@link
670 * InvocationTargetException} and {@link
671 * NoSuchMethodException}. Both of these exception types are
672 * subclasses of {@link ReflectiveOperationException}.
673 *
674 * @return a newly allocated instance of the class represented by this
675 * object.
676 * @throws IllegalAccessException if the class or its nullary
677 * constructor is not accessible.
678 * @throws InstantiationException
679 * if this {@code Class} represents an abstract class,
680 * an interface, an array class, a primitive type, or void;
681 * or if the class has no nullary constructor;
682 * or if the instantiation fails for some other reason.
683 * @throws ExceptionInInitializerError if the initialization
684 * provoked by this method fails.
685 */
686 @CallerSensitive
687 @Deprecated(since="9")
688 public T newInstance()
689 throws InstantiationException, IllegalAccessException
690 {
691 // Constructor lookup
692 Constructor<T> tmpConstructor = cachedConstructor;
693 if (tmpConstructor == null) {
694 if (this == Class.class) {
695 throw new IllegalAccessException(
696 "Can not call newInstance() on the Class for java.lang.Class"
697 );
698 }
699 try {
700 Class<?>[] empty = {};
701 final Constructor<T> c = getReflectionFactory().copyConstructor(
702 getConstructor0(empty, Member.DECLARED));
703 // Disable accessibility checks on the constructor
704 // access check is done with the true caller
705 c.setAccessible(true);
706 cachedConstructor = tmpConstructor = c;
707 } catch (NoSuchMethodException e) {
708 throw (InstantiationException)
709 new InstantiationException(getName()).initCause(e);
710 }
711 }
712
713 try {
714 Class<?> caller = Reflection.getCallerClass();
715 return getReflectionFactory().newInstance(tmpConstructor, null, caller);
716 } catch (InvocationTargetException e) {
717 Unsafe.getUnsafe().throwException(e.getTargetException());
718 // Not reached
719 return null;
720 }
721 }
722
723 private transient volatile Constructor<T> cachedConstructor;
724
725 /**
726 * Determines if the specified {@code Object} is assignment-compatible
727 * with the object represented by this {@code Class}. This method is
728 * the dynamic equivalent of the Java language {@code instanceof}
729 * operator. The method returns {@code true} if the specified
730 * {@code Object} argument is non-null and can be cast to the
731 * reference type represented by this {@code Class} object without
732 * raising a {@code ClassCastException.} It returns {@code false}
733 * otherwise.
734 *
735 * <p> Specifically, if this {@code Class} object represents a
736 * declared class, this method returns {@code true} if the specified
737 * {@code Object} argument is an instance of the represented class (or
738 * of any of its subclasses); it returns {@code false} otherwise. If
739 * this {@code Class} object represents an array class, this method
740 * returns {@code true} if the specified {@code Object} argument
741 * can be converted to an object of the array class by an identity
742 * conversion or by a widening reference conversion; it returns
743 * {@code false} otherwise. If this {@code Class} object
744 * represents an interface, this method returns {@code true} if the
745 * class or any superclass of the specified {@code Object} argument
746 * implements this interface; it returns {@code false} otherwise. If
747 * this {@code Class} object represents a primitive type, this method
748 * returns {@code false}.
749 *
750 * @param obj the object to check
751 * @return true if {@code obj} is an instance of this class
752 *
753 * @since 1.1
754 */
755 @IntrinsicCandidate
756 public native boolean isInstance(Object obj);
757
758
759 /**
760 * Determines if the class or interface represented by this
761 * {@code Class} object is either the same as, or is a superclass or
762 * superinterface of, the class or interface represented by the specified
763 * {@code Class} parameter. It returns {@code true} if so;
764 * otherwise it returns {@code false}. If this {@code Class}
765 * object represents a primitive type, this method returns
766 * {@code true} if the specified {@code Class} parameter is
767 * exactly this {@code Class} object; otherwise it returns
768 * {@code false}.
769 *
770 * <p> Specifically, this method tests whether the type represented by the
771 * specified {@code Class} parameter can be converted to the type
772 * represented by this {@code Class} object via an identity conversion
773 * or via a widening reference conversion. See <cite>The Java Language
774 * Specification</cite>, sections {@jls 5.1.1} and {@jls 5.1.4},
775 * for details.
776 *
777 * @param cls the {@code Class} object to be checked
778 * @return the {@code boolean} value indicating whether objects of the
779 * type {@code cls} can be assigned to objects of this class
780 * @throws NullPointerException if the specified Class parameter is
781 * null.
782 * @since 1.1
783 */
784 @IntrinsicCandidate
785 public native boolean isAssignableFrom(Class<?> cls);
786
787
788 /**
789 * Determines if this {@code Class} object represents an
790 * interface type.
791 *
792 * @return {@code true} if this {@code Class} object represents an interface;
793 * {@code false} otherwise.
794 */
795 public boolean isInterface() {
796 return Modifier.isInterface(modifiers);
797 }
798
799
800 /**
801 * Determines if this {@code Class} object represents an array class.
802 *
803 * @return {@code true} if this {@code Class} object represents an array class;
804 * {@code false} otherwise.
805 * @since 1.1
806 */
807 public boolean isArray() {
808 return componentType != null;
809 }
810
811
812 /**
813 * Determines if this {@code Class} object represents a primitive
814 * type or void.
815 *
816 * <p> There are nine predefined {@code Class} objects to
817 * represent the eight primitive types and void. These are
818 * created by the Java Virtual Machine, and have the same
819 * {@linkplain #getName() names} as the primitive types that they
820 * represent, namely {@code boolean}, {@code byte}, {@code char},
821 * {@code short}, {@code int}, {@code long}, {@code float}, and
822 * {@code double}.
823 *
824 * <p>No other class objects are considered primitive.
825 *
826 * @apiNote
827 * A {@code Class} object represented by a primitive type can be
828 * accessed via the {@code TYPE} public static final variables
829 * defined in the primitive wrapper classes such as {@link
830 * java.lang.Integer#TYPE Integer.TYPE}. In the Java programming
831 * language, the objects may be referred to by a class literal
832 * expression such as {@code int.class}. The {@code Class} object
833 * for void can be expressed as {@code void.class} or {@link
834 * java.lang.Void#TYPE Void.TYPE}.
835 *
836 * @return true if and only if this class represents a primitive type
837 *
838 * @see java.lang.Boolean#TYPE
839 * @see java.lang.Character#TYPE
840 * @see java.lang.Byte#TYPE
841 * @see java.lang.Short#TYPE
842 * @see java.lang.Integer#TYPE
843 * @see java.lang.Long#TYPE
844 * @see java.lang.Float#TYPE
845 * @see java.lang.Double#TYPE
846 * @see java.lang.Void#TYPE
847 * @since 1.1
848 * @jls 15.8.2 Class Literals
849 */
850 public boolean isPrimitive() {
851 return primitive;
852 }
853
854 /**
855 * Returns true if this {@code Class} object represents an annotation
856 * interface. Note that if this method returns true, {@link #isInterface()}
857 * would also return true, as all annotation interfaces are also interfaces.
858 *
859 * @return {@code true} if this {@code Class} object represents an annotation
860 * interface; {@code false} otherwise
861 * @since 1.5
862 */
863 public boolean isAnnotation() {
864 return (getModifiers() & ANNOTATION) != 0;
865 }
866
867 /**
868 *{@return {@code true} if and only if this class has the synthetic modifier
869 * bit set}
870 *
871 * @jls 13.1 The Form of a Binary
872 * @jvms 4.1 The {@code ClassFile} Structure
873 * @see <a
874 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
875 * programming language and JVM modeling in core reflection</a>
876 * @since 1.5
877 */
878 public boolean isSynthetic() {
879 return (getModifiers() & SYNTHETIC) != 0;
880 }
881
882 /**
883 * Returns the name of the entity (class, interface, array class,
884 * primitive type, or void) represented by this {@code Class} object.
885 *
886 * <p> If this {@code Class} object represents a class or interface,
887 * not an array class, then:
888 * <ul>
889 * <li> If the class or interface is not {@linkplain #isHidden() hidden},
890 * then the {@linkplain ClassLoader##binary-name binary name}
891 * of the class or interface is returned.
892 * <li> If the class or interface is hidden, then the result is a string
893 * of the form: {@code N + '/' + <suffix>}
894 * where {@code N} is the {@linkplain ClassLoader##binary-name binary name}
895 * indicated by the {@code class} file passed to
896 * {@link java.lang.invoke.MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
897 * Lookup::defineHiddenClass}, and {@code <suffix>} is an unqualified name.
898 * </ul>
899 *
900 * <p> If this {@code Class} object represents an array class, then
901 * the result is a string consisting of one or more '{@code [}' characters
902 * representing the depth of the array nesting, followed by the element
903 * type as encoded using the following table:
904 *
905 * <blockquote><table class="striped" id="nameFormat">
906 * <caption style="display:none">Element types and encodings</caption>
907 * <thead>
908 * <tr><th scope="col"> Element Type <th scope="col"> Encoding
909 * </thead>
910 * <tbody style="text-align:left">
911 * <tr><th scope="row"> {@code boolean} <td style="text-align:center"> {@code Z}
912 * <tr><th scope="row"> {@code byte} <td style="text-align:center"> {@code B}
913 * <tr><th scope="row"> {@code char} <td style="text-align:center"> {@code C}
914 * <tr><th scope="row"> class or interface with {@linkplain ClassLoader##binary-name binary name} <i>N</i>
915 * <td style="text-align:center"> {@code L}<em>N</em>{@code ;}
916 * <tr><th scope="row"> {@code double} <td style="text-align:center"> {@code D}
917 * <tr><th scope="row"> {@code float} <td style="text-align:center"> {@code F}
918 * <tr><th scope="row"> {@code int} <td style="text-align:center"> {@code I}
919 * <tr><th scope="row"> {@code long} <td style="text-align:center"> {@code J}
920 * <tr><th scope="row"> {@code short} <td style="text-align:center"> {@code S}
921 * </tbody>
922 * </table></blockquote>
923 *
924 * <p> If this {@code Class} object represents a primitive type or {@code void},
925 * then the result is a string with the same spelling as the Java language
926 * keyword which corresponds to the primitive type or {@code void}.
927 *
928 * <p> Examples:
929 * <blockquote><pre>
930 * String.class.getName()
931 * returns "java.lang.String"
932 * Character.UnicodeBlock.class.getName()
933 * returns "java.lang.Character$UnicodeBlock"
934 * byte.class.getName()
935 * returns "byte"
936 * (new Object[3]).getClass().getName()
937 * returns "[Ljava.lang.Object;"
938 * (new int[3][4][5][6][7][8][9]).getClass().getName()
939 * returns "[[[[[[[I"
940 * </pre></blockquote>
941 *
942 * @apiNote
943 * Distinct class objects can have the same name but different class loaders.
944 *
945 * @return the name of the class, interface, or other entity
946 * represented by this {@code Class} object.
947 * @jls 13.1 The Form of a Binary
948 */
949 public String getName() {
950 String name = this.name;
951 return name != null ? name : initClassName();
952 }
953
954 // Cache the name to reduce the number of calls into the VM.
955 // This field would be set by VM itself during initClassName call.
956 private transient String name;
957 private native String initClassName();
958
959 /**
960 * Returns the class loader for the class. Some implementations may use
961 * null to represent the bootstrap class loader. This method will return
962 * null in such implementations if this class was loaded by the bootstrap
963 * class loader.
964 *
965 * <p>If this {@code Class} object
966 * represents a primitive type or void, null is returned.
967 *
968 * @return the class loader that loaded the class or interface
969 * represented by this {@code Class} object.
970 * @see java.lang.ClassLoader
971 */
972 public ClassLoader getClassLoader() {
973 return classLoader;
974 }
975
976 // Package-private to allow ClassLoader access
977 ClassLoader getClassLoader0() { return classLoader; }
978
979 /**
980 * Returns the module that this class or interface is a member of.
981 *
982 * If this class represents an array type then this method returns the
983 * {@code Module} for the element type. If this class represents a
984 * primitive type or void, then the {@code Module} object for the
985 * {@code java.base} module is returned.
986 *
987 * If this class is in an unnamed module then the {@linkplain
988 * ClassLoader#getUnnamedModule() unnamed} {@code Module} of the class
989 * loader for this class is returned.
990 *
991 * @return the module that this class or interface is a member of
992 *
993 * @since 9
994 */
995 public Module getModule() {
996 return module;
997 }
998
999 // set by VM
1000 @Stable
1001 private transient Module module;
1002
1003 // Initialized in JVM not by private constructor
1004 // This field is filtered from reflection access, i.e. getDeclaredField
1005 // will throw NoSuchFieldException
1006 private final ClassLoader classLoader;
1007
1008 private transient Object classData; // Set by VM
1009 private transient Object[] signers; // Read by VM, mutable
1010 private final transient char modifiers; // Set by the VM
1011 private final transient boolean primitive; // Set by the VM if the Class is a primitive type.
1012
1013 // package-private
1014 Object getClassData() {
1015 return classData;
1016 }
1017
1018 /**
1019 * Returns an array of {@code TypeVariable} objects that represent the
1020 * type variables declared by the generic declaration represented by this
1021 * {@code GenericDeclaration} object, in declaration order. Returns an
1022 * array of length 0 if the underlying generic declaration declares no type
1023 * variables.
1024 *
1025 * @return an array of {@code TypeVariable} objects that represent
1026 * the type variables declared by this generic declaration
1027 * @throws java.lang.reflect.GenericSignatureFormatError if the generic
1028 * signature of this generic declaration does not conform to
1029 * the format specified in section {@jvms 4.7.9} of
1030 * <cite>The Java Virtual Machine Specification</cite>
1031 * @since 1.5
1032 */
1033 @SuppressWarnings("unchecked")
1034 public TypeVariable<Class<T>>[] getTypeParameters() {
1035 ClassRepository info = getGenericInfo();
1036 if (info != null)
1037 return (TypeVariable<Class<T>>[])info.getTypeParameters();
1038 else
1039 return (TypeVariable<Class<T>>[])new TypeVariable<?>[0];
1040 }
1041
1042
1043 /**
1044 * Returns the {@code Class} representing the direct superclass of the
1045 * entity (class, interface, primitive type or void) represented by
1046 * this {@code Class}. If this {@code Class} represents either the
1047 * {@code Object} class, an interface, a primitive type, or void, then
1048 * null is returned. If this {@code Class} object represents an array class
1049 * then the {@code Class} object representing the {@code Object} class is
1050 * returned.
1051 *
1052 * @return the direct superclass of the class represented by this {@code Class} object
1053 */
1054 @IntrinsicCandidate
1055 public native Class<? super T> getSuperclass();
1056
1057
1058 /**
1059 * Returns the {@code Type} representing the direct superclass of
1060 * the entity (class, interface, primitive type or void) represented by
1061 * this {@code Class} object.
1062 *
1063 * <p>If the superclass is a parameterized type, the {@code Type}
1064 * object returned must accurately reflect the actual type
1065 * arguments used in the source code. The parameterized type
1066 * representing the superclass is created if it had not been
1067 * created before. See the declaration of {@link
1068 * java.lang.reflect.ParameterizedType ParameterizedType} for the
1069 * semantics of the creation process for parameterized types. If
1070 * this {@code Class} object represents either the {@code Object}
1071 * class, an interface, a primitive type, or void, then null is
1072 * returned. If this {@code Class} object represents an array class
1073 * then the {@code Class} object representing the {@code Object} class is
1074 * returned.
1075 *
1076 * @throws java.lang.reflect.GenericSignatureFormatError if the generic
1077 * class signature does not conform to the format specified in
1078 * section {@jvms 4.7.9} of <cite>The Java Virtual
1079 * Machine Specification</cite>
1080 * @throws TypeNotPresentException if the generic superclass
1081 * refers to a non-existent type declaration
1082 * @throws java.lang.reflect.MalformedParameterizedTypeException if the
1083 * generic superclass refers to a parameterized type that cannot be
1084 * instantiated for any reason
1085 * @return the direct superclass of the class represented by this {@code Class} object
1086 * @since 1.5
1087 */
1088 public Type getGenericSuperclass() {
1089 ClassRepository info = getGenericInfo();
1090 if (info == null) {
1091 return getSuperclass();
1092 }
1093
1094 // Historical irregularity:
1095 // Generic signature marks interfaces with superclass = Object
1096 // but this API returns null for interfaces
1097 if (isInterface()) {
1098 return null;
1099 }
1100
1101 return info.getSuperclass();
1102 }
1103
1104 /**
1105 * Gets the package of this class.
1106 *
1107 * <p>If this class represents an array type, a primitive type or void,
1108 * this method returns {@code null}.
1109 *
1110 * @return the package of this class.
1111 */
1112 public Package getPackage() {
1113 if (isPrimitive() || isArray()) {
1114 return null;
1115 }
1116 ClassLoader cl = classLoader;
1117 return cl != null ? cl.definePackage(this)
1118 : BootLoader.definePackage(this);
1119 }
1120
1121 /**
1122 * Returns the fully qualified package name.
1123 *
1124 * <p> If this class is a top level class, then this method returns the fully
1125 * qualified name of the package that the class is a member of, or the
1126 * empty string if the class is in an unnamed package.
1127 *
1128 * <p> If this class is a member class, then this method is equivalent to
1129 * invoking {@code getPackageName()} on the {@linkplain #getEnclosingClass
1130 * enclosing class}.
1131 *
1132 * <p> If this class is a {@linkplain #isLocalClass local class} or an {@linkplain
1133 * #isAnonymousClass() anonymous class}, then this method is equivalent to
1134 * invoking {@code getPackageName()} on the {@linkplain #getDeclaringClass
1135 * declaring class} of the {@linkplain #getEnclosingMethod enclosing method} or
1136 * {@linkplain #getEnclosingConstructor enclosing constructor}.
1137 *
1138 * <p> If this class represents an array type then this method returns the
1139 * package name of the element type. If this class represents a primitive
1140 * type or void then the package name "{@code java.lang}" is returned.
1141 *
1142 * @return the fully qualified package name
1143 *
1144 * @since 9
1145 * @jls 6.7 Fully Qualified Names and Canonical Names
1146 */
1147 public String getPackageName() {
1148 String pn = this.packageName;
1149 if (pn == null) {
1150 Class<?> c = isArray() ? elementType() : this;
1151 if (c.isPrimitive()) {
1152 pn = "java.lang";
1153 } else {
1154 String cn = c.getName();
1155 int dot = cn.lastIndexOf('.');
1156 pn = (dot != -1) ? cn.substring(0, dot).intern() : "";
1157 }
1158 this.packageName = pn;
1159 }
1160 return pn;
1161 }
1162
1163 // cached package name
1164 private transient String packageName;
1165
1166 /**
1167 * Returns the interfaces directly implemented by the class or interface
1168 * represented by this {@code Class} object.
1169 *
1170 * <p>If this {@code Class} object represents a class, the return value is an array
1171 * containing objects representing all interfaces directly implemented by
1172 * the class. The order of the interface objects in the array corresponds
1173 * to the order of the interface names in the {@code implements} clause of
1174 * the declaration of the class represented by this {@code Class} object. For example,
1175 * given the declaration:
1176 * <blockquote>
1177 * {@code class Shimmer implements FloorWax, DessertTopping { ... }}
1178 * </blockquote>
1179 * suppose the value of {@code s} is an instance of
1180 * {@code Shimmer}; the value of the expression:
1181 * <blockquote>
1182 * {@code s.getClass().getInterfaces()[0]}
1183 * </blockquote>
1184 * is the {@code Class} object that represents interface
1185 * {@code FloorWax}; and the value of:
1186 * <blockquote>
1187 * {@code s.getClass().getInterfaces()[1]}
1188 * </blockquote>
1189 * is the {@code Class} object that represents interface
1190 * {@code DessertTopping}.
1191 *
1192 * <p>If this {@code Class} object represents an interface, the array contains objects
1193 * representing all interfaces directly extended by the interface. The
1194 * order of the interface objects in the array corresponds to the order of
1195 * the interface names in the {@code extends} clause of the declaration of
1196 * the interface represented by this {@code Class} object.
1197 *
1198 * <p>If this {@code Class} object represents a class or interface that implements no
1199 * interfaces, the method returns an array of length 0.
1200 *
1201 * <p>If this {@code Class} object represents a primitive type or void, the method
1202 * returns an array of length 0.
1203 *
1204 * <p>If this {@code Class} object represents an array type, the
1205 * interfaces {@code Cloneable} and {@code java.io.Serializable} are
1206 * returned in that order.
1207 *
1208 * @return an array of interfaces directly implemented by this class
1209 */
1210 public Class<?>[] getInterfaces() {
1211 // defensively copy before handing over to user code
1212 return getInterfaces(true);
1213 }
1214
1215 private Class<?>[] getInterfaces(boolean cloneArray) {
1216 ReflectionData<T> rd = reflectionData();
1217 Class<?>[] interfaces = rd.interfaces;
1218 if (interfaces == null) {
1219 interfaces = getInterfaces0();
1220 rd.interfaces = interfaces;
1221 }
1222 // defensively copy if requested
1223 return cloneArray ? interfaces.clone() : interfaces;
1224 }
1225
1226 private native Class<?>[] getInterfaces0();
1227
1228 /**
1229 * Returns the {@code Type}s representing the interfaces
1230 * directly implemented by the class or interface represented by
1231 * this {@code Class} object.
1232 *
1233 * <p>If a superinterface is a parameterized type, the
1234 * {@code Type} object returned for it must accurately reflect
1235 * the actual type arguments used in the source code. The
1236 * parameterized type representing each superinterface is created
1237 * if it had not been created before. See the declaration of
1238 * {@link java.lang.reflect.ParameterizedType ParameterizedType}
1239 * for the semantics of the creation process for parameterized
1240 * types.
1241 *
1242 * <p>If this {@code Class} object represents a class, the return value is an array
1243 * containing objects representing all interfaces directly implemented by
1244 * the class. The order of the interface objects in the array corresponds
1245 * to the order of the interface names in the {@code implements} clause of
1246 * the declaration of the class represented by this {@code Class} object.
1247 *
1248 * <p>If this {@code Class} object represents an interface, the array contains objects
1249 * representing all interfaces directly extended by the interface. The
1250 * order of the interface objects in the array corresponds to the order of
1251 * the interface names in the {@code extends} clause of the declaration of
1252 * the interface represented by this {@code Class} object.
1253 *
1254 * <p>If this {@code Class} object represents a class or interface that implements no
1255 * interfaces, the method returns an array of length 0.
1256 *
1257 * <p>If this {@code Class} object represents a primitive type or void, the method
1258 * returns an array of length 0.
1259 *
1260 * <p>If this {@code Class} object represents an array type, the
1261 * interfaces {@code Cloneable} and {@code java.io.Serializable} are
1262 * returned in that order.
1263 *
1264 * @throws java.lang.reflect.GenericSignatureFormatError
1265 * if the generic class signature does not conform to the
1266 * format specified in section {@jvms 4.7.9} of <cite>The
1267 * Java Virtual Machine Specification</cite>
1268 * @throws TypeNotPresentException if any of the generic
1269 * superinterfaces refers to a non-existent type declaration
1270 * @throws java.lang.reflect.MalformedParameterizedTypeException
1271 * if any of the generic superinterfaces refer to a parameterized
1272 * type that cannot be instantiated for any reason
1273 * @return an array of interfaces directly implemented by this class
1274 * @since 1.5
1275 */
1276 public Type[] getGenericInterfaces() {
1277 ClassRepository info = getGenericInfo();
1278 return (info == null) ? getInterfaces() : info.getSuperInterfaces();
1279 }
1280
1281
1282 /**
1283 * Returns the {@code Class} representing the component type of an
1284 * array. If this class does not represent an array class this method
1285 * returns null.
1286 *
1287 * @return the {@code Class} representing the component type of this
1288 * class if this class is an array
1289 * @see java.lang.reflect.Array
1290 * @since 1.1
1291 */
1292 public Class<?> getComponentType() {
1293 return componentType;
1294 }
1295
1296 // The componentType field's null value is the sole indication that the class
1297 // is an array - see isArray().
1298 private transient final Class<?> componentType;
1299
1300 /*
1301 * Returns the {@code Class} representing the element type of an array class.
1302 * If this class does not represent an array class, then this method returns
1303 * {@code null}.
1304 */
1305 private Class<?> elementType() {
1306 if (!isArray()) return null;
1307
1308 Class<?> c = this;
1309 while (c.isArray()) {
1310 c = c.getComponentType();
1311 }
1312 return c;
1313 }
1314
1315 /**
1316 * Returns the Java language modifiers for this class or interface, encoded
1317 * in an integer. The modifiers consist of the Java Virtual Machine's
1318 * constants for {@code public}, {@code protected},
1319 * {@code private}, {@code final}, {@code static},
1320 * {@code abstract} and {@code interface}; they should be decoded
1321 * using the methods of class {@code Modifier}.
1322 *
1323 * <p> If the underlying class is an array class:
1324 * <ul>
1325 * <li> its {@code public}, {@code private} and {@code protected}
1326 * modifiers are the same as those of its component type
1327 * <li> its {@code abstract} and {@code final} modifiers are always
1328 * {@code true}
1329 * <li> its interface modifier is always {@code false}, even when
1330 * the component type is an interface
1331 * </ul>
1332 * If this {@code Class} object represents a primitive type or
1333 * void, its {@code public}, {@code abstract}, and {@code final}
1334 * modifiers are always {@code true}.
1335 * For {@code Class} objects representing void, primitive types, and
1336 * arrays, the values of other modifiers are {@code false} other
1337 * than as specified above.
1338 *
1339 * <p> The modifier encodings are defined in section {@jvms 4.1}
1340 * of <cite>The Java Virtual Machine Specification</cite>.
1341 *
1342 * @return the {@code int} representing the modifiers for this class
1343 * @see java.lang.reflect.Modifier
1344 * @see #accessFlags()
1345 * @see <a
1346 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
1347 * programming language and JVM modeling in core reflection</a>
1348 * @since 1.1
1349 * @jls 8.1.1 Class Modifiers
1350 * @jls 9.1.1 Interface Modifiers
1351 * @jvms 4.1 The {@code ClassFile} Structure
1352 */
1353 public int getModifiers() { return modifiers; }
1354
1355 /**
1356 * {@return an unmodifiable set of the {@linkplain AccessFlag access
1357 * flags} for this class, possibly empty}
1358 *
1359 * <p> If the underlying class is an array class:
1360 * <ul>
1361 * <li> its {@code PUBLIC}, {@code PRIVATE} and {@code PROTECTED}
1362 * access flags are the same as those of its component type
1363 * <li> its {@code ABSTRACT} and {@code FINAL} flags are present
1364 * <li> its {@code INTERFACE} flag is absent, even when the
1365 * component type is an interface
1366 * </ul>
1367 * If this {@code Class} object represents a primitive type or
1368 * void, the flags are {@code PUBLIC}, {@code ABSTRACT}, and
1369 * {@code FINAL}.
1370 * For {@code Class} objects representing void, primitive types, and
1371 * arrays, access flags are absent other than as specified above.
1372 *
1373 * @see #getModifiers()
1374 * @jvms 4.1 The ClassFile Structure
1375 * @jvms 4.7.6 The InnerClasses Attribute
1376 * @since 20
1377 */
1378 public Set<AccessFlag> accessFlags() {
1379 // Location.CLASS allows SUPER and AccessFlag.MODULE which
1380 // INNER_CLASS forbids. INNER_CLASS allows PRIVATE, PROTECTED,
1381 // and STATIC, which are not allowed on Location.CLASS.
1382 // Use getClassAccessFlagsRaw to expose SUPER status.
1383 var location = (isMemberClass() || isLocalClass() ||
1384 isAnonymousClass() || isArray()) ?
1385 AccessFlag.Location.INNER_CLASS :
1386 AccessFlag.Location.CLASS;
1387 return getReflectionFactory().parseAccessFlags((location == AccessFlag.Location.CLASS) ?
1388 getClassAccessFlagsRaw() : getModifiers(), location, this);
1389 }
1390
1391 /**
1392 * Gets the signers of this class.
1393 *
1394 * @return the signers of this class, or null if there are no signers. In
1395 * particular, this method returns null if this {@code Class} object represents
1396 * a primitive type or void.
1397 * @since 1.1
1398 */
1399 public Object[] getSigners() {
1400 var signers = this.signers;
1401 return signers == null ? null : signers.clone();
1402 }
1403
1404 /**
1405 * Set the signers of this class.
1406 */
1407 void setSigners(Object[] signers) {
1408 if (!isPrimitive() && !isArray()) {
1409 this.signers = signers;
1410 }
1411 }
1412
1413 /**
1414 * If this {@code Class} object represents a local or anonymous
1415 * class within a method, returns a {@link
1416 * java.lang.reflect.Method Method} object representing the
1417 * immediately enclosing method of the underlying class. Returns
1418 * {@code null} otherwise.
1419 *
1420 * In particular, this method returns {@code null} if the underlying
1421 * class is a local or anonymous class immediately enclosed by a class or
1422 * interface declaration, instance initializer or static initializer.
1423 *
1424 * @return the immediately enclosing method of the underlying class, if
1425 * that class is a local or anonymous class; otherwise {@code null}.
1426 *
1427 * @since 1.5
1428 */
1429 public Method getEnclosingMethod() {
1430 EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
1431
1432 if (enclosingInfo == null)
1433 return null;
1434 else {
1435 if (!enclosingInfo.isMethod())
1436 return null;
1437
1438 MethodRepository typeInfo = MethodRepository.make(enclosingInfo.getDescriptor(),
1439 getFactory());
1440 Class<?> returnType = toClass(typeInfo.getReturnType());
1441 Type [] parameterTypes = typeInfo.getParameterTypes();
1442 Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];
1443
1444 // Convert Types to Classes; returned types *should*
1445 // be class objects since the methodDescriptor's used
1446 // don't have generics information
1447 for(int i = 0; i < parameterClasses.length; i++)
1448 parameterClasses[i] = toClass(parameterTypes[i]);
1449
1450 final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
1451 Method[] candidates = enclosingCandidate.privateGetDeclaredMethods(false);
1452
1453 /*
1454 * Loop over all declared methods; match method name,
1455 * number of and type of parameters, *and* return
1456 * type. Matching return type is also necessary
1457 * because of covariant returns, etc.
1458 */
1459 ReflectionFactory fact = getReflectionFactory();
1460 for (Method m : candidates) {
1461 if (m.getName().equals(enclosingInfo.getName()) &&
1462 arrayContentsEq(parameterClasses,
1463 fact.getExecutableSharedParameterTypes(m))) {
1464 // finally, check return type
1465 if (m.getReturnType().equals(returnType)) {
1466 return fact.copyMethod(m);
1467 }
1468 }
1469 }
1470
1471 throw new InternalError("Enclosing method not found");
1472 }
1473 }
1474
1475 private native Object[] getEnclosingMethod0();
1476
1477 private EnclosingMethodInfo getEnclosingMethodInfo() {
1478 Object[] enclosingInfo = getEnclosingMethod0();
1479 if (enclosingInfo == null)
1480 return null;
1481 else {
1482 return new EnclosingMethodInfo(enclosingInfo);
1483 }
1484 }
1485
1486 private static final class EnclosingMethodInfo {
1487 private final Class<?> enclosingClass;
1488 private final String name;
1489 private final String descriptor;
1490
1491 static void validate(Object[] enclosingInfo) {
1492 if (enclosingInfo.length != 3)
1493 throw new InternalError("Malformed enclosing method information");
1494 try {
1495 // The array is expected to have three elements:
1496
1497 // the immediately enclosing class
1498 Class<?> enclosingClass = (Class<?>)enclosingInfo[0];
1499 assert(enclosingClass != null);
1500
1501 // the immediately enclosing method or constructor's
1502 // name (can be null).
1503 String name = (String)enclosingInfo[1];
1504
1505 // the immediately enclosing method or constructor's
1506 // descriptor (null iff name is).
1507 String descriptor = (String)enclosingInfo[2];
1508 assert((name != null && descriptor != null) || name == descriptor);
1509 } catch (ClassCastException cce) {
1510 throw new InternalError("Invalid type in enclosing method information", cce);
1511 }
1512 }
1513
1514 EnclosingMethodInfo(Object[] enclosingInfo) {
1515 validate(enclosingInfo);
1516 this.enclosingClass = (Class<?>)enclosingInfo[0];
1517 this.name = (String)enclosingInfo[1];
1518 this.descriptor = (String)enclosingInfo[2];
1519 }
1520
1521 boolean isPartial() {
1522 return enclosingClass == null || name == null || descriptor == null;
1523 }
1524
1525 boolean isConstructor() { return !isPartial() && ConstantDescs.INIT_NAME.equals(name); }
1526
1527 boolean isMethod() { return !isPartial() && !isConstructor() && !ConstantDescs.CLASS_INIT_NAME.equals(name); }
1528
1529 Class<?> getEnclosingClass() { return enclosingClass; }
1530
1531 String getName() { return name; }
1532
1533 String getDescriptor() { return descriptor; }
1534
1535 }
1536
1537 private static Class<?> toClass(Type o) {
1538 if (o instanceof GenericArrayType gat)
1539 return toClass(gat.getGenericComponentType()).arrayType();
1540 return (Class<?>)o;
1541 }
1542
1543 /**
1544 * If this {@code Class} object represents a local or anonymous
1545 * class within a constructor, returns a {@link
1546 * java.lang.reflect.Constructor Constructor} object representing
1547 * the immediately enclosing constructor of the underlying
1548 * class. Returns {@code null} otherwise. In particular, this
1549 * method returns {@code null} if the underlying class is a local
1550 * or anonymous class immediately enclosed by a class or
1551 * interface declaration, instance initializer or static initializer.
1552 *
1553 * @return the immediately enclosing constructor of the underlying class, if
1554 * that class is a local or anonymous class; otherwise {@code null}.
1555 *
1556 * @since 1.5
1557 */
1558 public Constructor<?> getEnclosingConstructor() {
1559 EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
1560
1561 if (enclosingInfo == null)
1562 return null;
1563 else {
1564 if (!enclosingInfo.isConstructor())
1565 return null;
1566
1567 ConstructorRepository typeInfo = ConstructorRepository.make(enclosingInfo.getDescriptor(),
1568 getFactory());
1569 Type [] parameterTypes = typeInfo.getParameterTypes();
1570 Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];
1571
1572 // Convert Types to Classes; returned types *should*
1573 // be class objects since the methodDescriptor's used
1574 // don't have generics information
1575 for (int i = 0; i < parameterClasses.length; i++)
1576 parameterClasses[i] = toClass(parameterTypes[i]);
1577
1578
1579 final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
1580 Constructor<?>[] candidates = enclosingCandidate
1581 .privateGetDeclaredConstructors(false);
1582 /*
1583 * Loop over all declared constructors; match number
1584 * of and type of parameters.
1585 */
1586 ReflectionFactory fact = getReflectionFactory();
1587 for (Constructor<?> c : candidates) {
1588 if (arrayContentsEq(parameterClasses,
1589 fact.getExecutableSharedParameterTypes(c))) {
1590 return fact.copyConstructor(c);
1591 }
1592 }
1593
1594 throw new InternalError("Enclosing constructor not found");
1595 }
1596 }
1597
1598
1599 /**
1600 * If the class or interface represented by this {@code Class} object
1601 * is a member of another class, returns the {@code Class} object
1602 * representing the class in which it was declared. This method returns
1603 * null if this class or interface is not a member of any other class. If
1604 * this {@code Class} object represents an array class, a primitive
1605 * type, or void, then this method returns null.
1606 *
1607 * @return the declaring class for this class
1608 * @since 1.1
1609 */
1610 public Class<?> getDeclaringClass() {
1611 return getDeclaringClass0();
1612 }
1613
1614 private native Class<?> getDeclaringClass0();
1615
1616
1617 /**
1618 * Returns the immediately enclosing class of the underlying
1619 * class. If the underlying class is a top level class this
1620 * method returns {@code null}.
1621 * @return the immediately enclosing class of the underlying class
1622 * @since 1.5
1623 */
1624 public Class<?> getEnclosingClass() {
1625 // There are five kinds of classes (or interfaces):
1626 // a) Top level classes
1627 // b) Nested classes (static member classes)
1628 // c) Inner classes (non-static member classes)
1629 // d) Local classes (named classes declared within a method)
1630 // e) Anonymous classes
1631
1632
1633 // JVM Spec 4.7.7: A class must have an EnclosingMethod
1634 // attribute if and only if it is a local class or an
1635 // anonymous class.
1636 EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
1637 Class<?> enclosingCandidate;
1638
1639 if (enclosingInfo == null) {
1640 // This is a top level or a nested class or an inner class (a, b, or c)
1641 enclosingCandidate = getDeclaringClass0();
1642 } else {
1643 Class<?> enclosingClass = enclosingInfo.getEnclosingClass();
1644 // This is a local class or an anonymous class (d or e)
1645 if (enclosingClass == this || enclosingClass == null)
1646 throw new InternalError("Malformed enclosing method information");
1647 else
1648 enclosingCandidate = enclosingClass;
1649 }
1650 return enclosingCandidate;
1651 }
1652
1653 /**
1654 * Returns the simple name of the underlying class as given in the
1655 * source code. An empty string is returned if the underlying class is
1656 * {@linkplain #isAnonymousClass() anonymous}.
1657 * A {@linkplain #isSynthetic() synthetic class}, one not present
1658 * in source code, can have a non-empty name including special
1659 * characters, such as "{@code $}".
1660 *
1661 * <p>The simple name of an {@linkplain #isArray() array class} is the simple name of the
1662 * component type with "[]" appended. In particular the simple
1663 * name of an array class whose component type is anonymous is "[]".
1664 *
1665 * @return the simple name of the underlying class
1666 * @since 1.5
1667 */
1668 public String getSimpleName() {
1669 ReflectionData<T> rd = reflectionData();
1670 String simpleName = rd.simpleName;
1671 if (simpleName == null) {
1672 rd.simpleName = simpleName = getSimpleName0();
1673 }
1674 return simpleName;
1675 }
1676
1677 private String getSimpleName0() {
1678 if (isArray()) {
1679 return getComponentType().getSimpleName().concat("[]");
1680 }
1681 String simpleName = getSimpleBinaryName();
1682 if (simpleName == null) { // top level class
1683 simpleName = getName();
1684 simpleName = simpleName.substring(simpleName.lastIndexOf('.') + 1); // strip the package name
1685 }
1686 return simpleName;
1687 }
1688
1689 /**
1690 * Return an informative string for the name of this class or interface.
1691 *
1692 * @return an informative string for the name of this class or interface
1693 * @since 1.8
1694 */
1695 public String getTypeName() {
1696 if (isArray()) {
1697 try {
1698 Class<?> cl = this;
1699 int dimensions = 0;
1700 do {
1701 dimensions++;
1702 cl = cl.getComponentType();
1703 } while (cl.isArray());
1704 return cl.getName().concat("[]".repeat(dimensions));
1705 } catch (Throwable e) { /*FALLTHRU*/ }
1706 }
1707 return getName();
1708 }
1709
1710 /**
1711 * Returns the canonical name of the underlying class as
1712 * defined by <cite>The Java Language Specification</cite>.
1713 * Returns {@code null} if the underlying class does not have a canonical
1714 * name. Classes without canonical names include:
1715 * <ul>
1716 * <li>a {@linkplain #isLocalClass() local class}
1717 * <li>a {@linkplain #isAnonymousClass() anonymous class}
1718 * <li>a {@linkplain #isHidden() hidden class}
1719 * <li>an array whose component type does not have a canonical name</li>
1720 * </ul>
1721 *
1722 * The canonical name for a primitive class is the keyword for the
1723 * corresponding primitive type ({@code byte}, {@code short},
1724 * {@code char}, {@code int}, and so on).
1725 *
1726 * <p>An array type has a canonical name if and only if its
1727 * component type has a canonical name. When an array type has a
1728 * canonical name, it is equal to the canonical name of the
1729 * component type followed by "{@code []}".
1730 *
1731 * @return the canonical name of the underlying class if it exists, and
1732 * {@code null} otherwise.
1733 * @jls 6.7 Fully Qualified Names and Canonical Names
1734 * @since 1.5
1735 */
1736 public String getCanonicalName() {
1737 ReflectionData<T> rd = reflectionData();
1738 String canonicalName = rd.canonicalName;
1739 if (canonicalName == null) {
1740 rd.canonicalName = canonicalName = getCanonicalName0();
1741 }
1742 return canonicalName == ReflectionData.NULL_SENTINEL? null : canonicalName;
1743 }
1744
1745 private String getCanonicalName0() {
1746 if (isArray()) {
1747 String canonicalName = getComponentType().getCanonicalName();
1748 if (canonicalName != null)
1749 return canonicalName.concat("[]");
1750 else
1751 return ReflectionData.NULL_SENTINEL;
1752 }
1753 if (isHidden() || isLocalOrAnonymousClass())
1754 return ReflectionData.NULL_SENTINEL;
1755 Class<?> enclosingClass = getEnclosingClass();
1756 if (enclosingClass == null) { // top level class
1757 return getName();
1758 } else {
1759 String enclosingName = enclosingClass.getCanonicalName();
1760 if (enclosingName == null)
1761 return ReflectionData.NULL_SENTINEL;
1762 String simpleName = getSimpleName();
1763 return new StringBuilder(enclosingName.length() + simpleName.length() + 1)
1764 .append(enclosingName)
1765 .append('.')
1766 .append(simpleName)
1767 .toString();
1768 }
1769 }
1770
1771 /**
1772 * Returns {@code true} if and only if the underlying class
1773 * is an anonymous class.
1774 *
1775 * @apiNote
1776 * An anonymous class is not a {@linkplain #isHidden() hidden class}.
1777 *
1778 * @return {@code true} if and only if this class is an anonymous class.
1779 * @since 1.5
1780 * @jls 15.9.5 Anonymous Class Declarations
1781 */
1782 public boolean isAnonymousClass() {
1783 return !isArray() && isLocalOrAnonymousClass() &&
1784 getSimpleBinaryName0() == null;
1785 }
1786
1787 /**
1788 * Returns {@code true} if and only if the underlying class
1789 * is a local class.
1790 *
1791 * @return {@code true} if and only if this class is a local class.
1792 * @since 1.5
1793 * @jls 14.3 Local Class and Interface Declarations
1794 */
1795 public boolean isLocalClass() {
1796 return isLocalOrAnonymousClass() &&
1797 (isArray() || getSimpleBinaryName0() != null);
1798 }
1799
1800 /**
1801 * Returns {@code true} if and only if the underlying class
1802 * is a member class.
1803 *
1804 * @return {@code true} if and only if this class is a member class.
1805 * @since 1.5
1806 * @jls 8.5 Member Class and Interface Declarations
1807 */
1808 public boolean isMemberClass() {
1809 return !isLocalOrAnonymousClass() && getDeclaringClass0() != null;
1810 }
1811
1812 /**
1813 * Returns the "simple binary name" of the underlying class, i.e.,
1814 * the binary name without the leading enclosing class name.
1815 * Returns {@code null} if the underlying class is a top level
1816 * class.
1817 */
1818 private String getSimpleBinaryName() {
1819 if (isTopLevelClass())
1820 return null;
1821 String name = getSimpleBinaryName0();
1822 if (name == null) // anonymous class
1823 return "";
1824 return name;
1825 }
1826
1827 private native String getSimpleBinaryName0();
1828
1829 /**
1830 * Returns {@code true} if this is a top level class. Returns {@code false}
1831 * otherwise.
1832 */
1833 private boolean isTopLevelClass() {
1834 return !isLocalOrAnonymousClass() && getDeclaringClass0() == null;
1835 }
1836
1837 /**
1838 * Returns {@code true} if this is a local class or an anonymous
1839 * class. Returns {@code false} otherwise.
1840 */
1841 private boolean isLocalOrAnonymousClass() {
1842 // JVM Spec 4.7.7: A class must have an EnclosingMethod
1843 // attribute if and only if it is a local class or an
1844 // anonymous class.
1845 return hasEnclosingMethodInfo();
1846 }
1847
1848 private boolean hasEnclosingMethodInfo() {
1849 Object[] enclosingInfo = getEnclosingMethod0();
1850 if (enclosingInfo != null) {
1851 EnclosingMethodInfo.validate(enclosingInfo);
1852 return true;
1853 }
1854 return false;
1855 }
1856
1857 /**
1858 * Returns an array containing {@code Class} objects representing all
1859 * the public classes and interfaces that are members of the class
1860 * represented by this {@code Class} object. This includes public
1861 * class and interface members inherited from superclasses and public class
1862 * and interface members declared by the class. This method returns an
1863 * array of length 0 if this {@code Class} object has no public member
1864 * classes or interfaces. This method also returns an array of length 0 if
1865 * this {@code Class} object represents a primitive type, an array
1866 * class, or void.
1867 *
1868 * @return the array of {@code Class} objects representing the public
1869 * members of this class
1870 * @since 1.1
1871 */
1872 public Class<?>[] getClasses() {
1873 List<Class<?>> list = new ArrayList<>();
1874 Class<?> currentClass = Class.this;
1875 while (currentClass != null) {
1876 for (Class<?> m : currentClass.getDeclaredClasses()) {
1877 if (Modifier.isPublic(m.getModifiers())) {
1878 list.add(m);
1879 }
1880 }
1881 currentClass = currentClass.getSuperclass();
1882 }
1883 return list.toArray(new Class<?>[0]);
1884 }
1885
1886
1887 /**
1888 * Returns an array containing {@code Field} objects reflecting all
1889 * the accessible public fields of the class or interface represented by
1890 * this {@code Class} object.
1891 *
1892 * <p> If this {@code Class} object represents a class or interface with
1893 * no accessible public fields, then this method returns an array of length
1894 * 0.
1895 *
1896 * <p> If this {@code Class} object represents a class, then this method
1897 * returns the public fields of the class and of all its superclasses and
1898 * superinterfaces.
1899 *
1900 * <p> If this {@code Class} object represents an interface, then this
1901 * method returns the fields of the interface and of all its
1902 * superinterfaces.
1903 *
1904 * <p> If this {@code Class} object represents an array type, a primitive
1905 * type, or void, then this method returns an array of length 0.
1906 *
1907 * <p> The elements in the returned array are not sorted and are not in any
1908 * particular order.
1909 *
1910 * @return the array of {@code Field} objects representing the
1911 * public fields
1912 *
1913 * @since 1.1
1914 * @jls 8.2 Class Members
1915 * @jls 8.3 Field Declarations
1916 */
1917 public Field[] getFields() {
1918 return copyFields(privateGetPublicFields());
1919 }
1920
1921
1922 /**
1923 * Returns an array containing {@code Method} objects reflecting all the
1924 * public methods of the class or interface represented by this {@code
1925 * Class} object, including those declared by the class or interface and
1926 * those inherited from superclasses and superinterfaces.
1927 *
1928 * <p> If this {@code Class} object represents an array type, then the
1929 * returned array has a {@code Method} object for each of the public
1930 * methods inherited by the array type from {@code Object}. It does not
1931 * contain a {@code Method} object for {@code clone()}.
1932 *
1933 * <p> If this {@code Class} object represents an interface then the
1934 * returned array does not contain any implicitly declared methods from
1935 * {@code Object}. Therefore, if no methods are explicitly declared in
1936 * this interface or any of its superinterfaces then the returned array
1937 * has length 0. (Note that a {@code Class} object which represents a class
1938 * always has public methods, inherited from {@code Object}.)
1939 *
1940 * <p> The returned array never contains methods with names {@value
1941 * ConstantDescs#INIT_NAME} or {@value ConstantDescs#CLASS_INIT_NAME}.
1942 *
1943 * <p> The elements in the returned array are not sorted and are not in any
1944 * particular order.
1945 *
1946 * <p> Generally, the result is computed as with the following 4 step algorithm.
1947 * Let C be the class or interface represented by this {@code Class} object:
1948 * <ol>
1949 * <li> A union of methods is composed of:
1950 * <ol type="a">
1951 * <li> C's declared public instance and static methods as returned by
1952 * {@link #getDeclaredMethods()} and filtered to include only public
1953 * methods.</li>
1954 * <li> If C is a class other than {@code Object}, then include the result
1955 * of invoking this algorithm recursively on the superclass of C.</li>
1956 * <li> Include the results of invoking this algorithm recursively on all
1957 * direct superinterfaces of C, but include only instance methods.</li>
1958 * </ol></li>
1959 * <li> Union from step 1 is partitioned into subsets of methods with same
1960 * signature (name, parameter types) and return type.</li>
1961 * <li> Within each such subset only the most specific methods are selected.
1962 * Let method M be a method from a set of methods with same signature
1963 * and return type. M is most specific if there is no such method
1964 * N != M from the same set, such that N is more specific than M.
1965 * N is more specific than M if:
1966 * <ol type="a">
1967 * <li> N is declared by a class and M is declared by an interface; or</li>
1968 * <li> N and M are both declared by classes or both by interfaces and
1969 * N's declaring type is the same as or a subtype of M's declaring type
1970 * (clearly, if M's and N's declaring types are the same type, then
1971 * M and N are the same method).</li>
1972 * </ol></li>
1973 * <li> The result of this algorithm is the union of all selected methods from
1974 * step 3.</li>
1975 * </ol>
1976 *
1977 * @apiNote There may be more than one method with a particular name
1978 * and parameter types in a class because while the Java language forbids a
1979 * class to declare multiple methods with the same signature but different
1980 * return types, the Java virtual machine does not. This
1981 * increased flexibility in the virtual machine can be used to
1982 * implement various language features. For example, covariant
1983 * returns can be implemented with {@linkplain
1984 * java.lang.reflect.Method#isBridge bridge methods}; the bridge
1985 * method and the overriding method would have the same
1986 * signature but different return types.
1987 *
1988 * @return the array of {@code Method} objects representing the
1989 * public methods of this class
1990 *
1991 * @jls 8.2 Class Members
1992 * @jls 8.4 Method Declarations
1993 * @since 1.1
1994 */
1995 public Method[] getMethods() {
1996 return copyMethods(privateGetPublicMethods());
1997 }
1998
1999
2000 /**
2001 * Returns an array containing {@code Constructor} objects reflecting
2002 * all the public constructors of the class represented by this
2003 * {@code Class} object. An array of length 0 is returned if the
2004 * class has no public constructors, or if the class is an array class, or
2005 * if the class reflects a primitive type or void.
2006 *
2007 * @apiNote
2008 * While this method returns an array of {@code
2009 * Constructor<T>} objects (that is an array of constructors from
2010 * this class), the return type of this method is {@code
2011 * Constructor<?>[]} and <em>not</em> {@code Constructor<T>[]} as
2012 * might be expected. This less informative return type is
2013 * necessary since after being returned from this method, the
2014 * array could be modified to hold {@code Constructor} objects for
2015 * different classes, which would violate the type guarantees of
2016 * {@code Constructor<T>[]}.
2017 *
2018 * @return the array of {@code Constructor} objects representing the
2019 * public constructors of this class
2020 *
2021 * @see #getDeclaredConstructors()
2022 * @since 1.1
2023 */
2024 public Constructor<?>[] getConstructors() {
2025 return copyConstructors(privateGetDeclaredConstructors(true));
2026 }
2027
2028
2029 /**
2030 * Returns a {@code Field} object that reflects the specified public member
2031 * field of the class or interface represented by this {@code Class}
2032 * object. The {@code name} parameter is a {@code String} specifying the
2033 * simple name of the desired field.
2034 *
2035 * <p> The field to be reflected is determined by the algorithm that
2036 * follows. Let C be the class or interface represented by this {@code Class} object:
2037 *
2038 * <OL>
2039 * <LI> If C declares a public field with the name specified, that is the
2040 * field to be reflected.</LI>
2041 * <LI> If no field was found in step 1 above, this algorithm is applied
2042 * recursively to each direct superinterface of C. The direct
2043 * superinterfaces are searched in the order they were declared.</LI>
2044 * <LI> If no field was found in steps 1 and 2 above, and C has a
2045 * superclass S, then this algorithm is invoked recursively upon S.
2046 * If C has no superclass, then a {@code NoSuchFieldException}
2047 * is thrown.</LI>
2048 * </OL>
2049 *
2050 * <p> If this {@code Class} object represents an array type, then this
2051 * method does not find the {@code length} field of the array type.
2052 *
2053 * @param name the field name
2054 * @return the {@code Field} object of this class specified by
2055 * {@code name}
2056 * @throws NoSuchFieldException if a field with the specified name is
2057 * not found.
2058 * @throws NullPointerException if {@code name} is {@code null}
2059 *
2060 * @since 1.1
2061 * @jls 8.2 Class Members
2062 * @jls 8.3 Field Declarations
2063 */
2064 public Field getField(String name) throws NoSuchFieldException {
2065 Objects.requireNonNull(name);
2066 Field field = getField0(name);
2067 if (field == null) {
2068 throw new NoSuchFieldException(name);
2069 }
2070 return getReflectionFactory().copyField(field);
2071 }
2072
2073
2074 /**
2075 * Returns a {@code Method} object that reflects the specified public
2076 * member method of the class or interface represented by this
2077 * {@code Class} object. The {@code name} parameter is a
2078 * {@code String} specifying the simple name of the desired method. The
2079 * {@code parameterTypes} parameter is an array of {@code Class}
2080 * objects that identify the method's formal parameter types, in declared
2081 * order. If {@code parameterTypes} is {@code null}, it is
2082 * treated as if it were an empty array.
2083 *
2084 * <p> If this {@code Class} object represents an array type, then this
2085 * method finds any public method inherited by the array type from
2086 * {@code Object} except method {@code clone()}.
2087 *
2088 * <p> If this {@code Class} object represents an interface then this
2089 * method does not find any implicitly declared method from
2090 * {@code Object}. Therefore, if no methods are explicitly declared in
2091 * this interface or any of its superinterfaces, then this method does not
2092 * find any method.
2093 *
2094 * <p> This method does not find any method with name {@value
2095 * ConstantDescs#INIT_NAME} or {@value ConstantDescs#CLASS_INIT_NAME}.
2096 *
2097 * <p> Generally, the method to be reflected is determined by the 4 step
2098 * algorithm that follows.
2099 * Let C be the class or interface represented by this {@code Class} object:
2100 * <ol>
2101 * <li> A union of methods is composed of:
2102 * <ol type="a">
2103 * <li> C's declared public instance and static methods as returned by
2104 * {@link #getDeclaredMethods()} and filtered to include only public
2105 * methods that match given {@code name} and {@code parameterTypes}</li>
2106 * <li> If C is a class other than {@code Object}, then include the result
2107 * of invoking this algorithm recursively on the superclass of C.</li>
2108 * <li> Include the results of invoking this algorithm recursively on all
2109 * direct superinterfaces of C, but include only instance methods.</li>
2110 * </ol></li>
2111 * <li> This union is partitioned into subsets of methods with same
2112 * return type (the selection of methods from step 1 also guarantees that
2113 * they have the same method name and parameter types).</li>
2114 * <li> Within each such subset only the most specific methods are selected.
2115 * Let method M be a method from a set of methods with same VM
2116 * signature (return type, name, parameter types).
2117 * M is most specific if there is no such method N != M from the same
2118 * set, such that N is more specific than M. N is more specific than M
2119 * if:
2120 * <ol type="a">
2121 * <li> N is declared by a class and M is declared by an interface; or</li>
2122 * <li> N and M are both declared by classes or both by interfaces and
2123 * N's declaring type is the same as or a subtype of M's declaring type
2124 * (clearly, if M's and N's declaring types are the same type, then
2125 * M and N are the same method).</li>
2126 * </ol></li>
2127 * <li> The result of this algorithm is chosen arbitrarily from the methods
2128 * with most specific return type among all selected methods from step 3.
2129 * Let R be a return type of a method M from the set of all selected methods
2130 * from step 3. M is a method with most specific return type if there is
2131 * no such method N != M from the same set, having return type S != R,
2132 * such that S is a subtype of R as determined by
2133 * R.class.{@link #isAssignableFrom}(S.class).
2134 * </ol>
2135 *
2136 * @apiNote There may be more than one method with matching name and
2137 * parameter types in a class because while the Java language forbids a
2138 * class to declare multiple methods with the same signature but different
2139 * return types, the Java virtual machine does not. This
2140 * increased flexibility in the virtual machine can be used to
2141 * implement various language features. For example, covariant
2142 * returns can be implemented with {@linkplain
2143 * java.lang.reflect.Method#isBridge bridge methods}; the bridge
2144 * method and the overriding method would have the same
2145 * signature but different return types. This method would return the
2146 * overriding method as it would have a more specific return type.
2147 *
2148 * @param name the name of the method
2149 * @param parameterTypes the list of parameters
2150 * @return the {@code Method} object that matches the specified
2151 * {@code name} and {@code parameterTypes}
2152 * @throws NoSuchMethodException if a matching method is not found
2153 * or if the name is {@value ConstantDescs#INIT_NAME} or
2154 * {@value ConstantDescs#CLASS_INIT_NAME}.
2155 * @throws NullPointerException if {@code name} is {@code null}
2156 *
2157 * @jls 8.2 Class Members
2158 * @jls 8.4 Method Declarations
2159 * @since 1.1
2160 */
2161 public Method getMethod(String name, Class<?>... parameterTypes)
2162 throws NoSuchMethodException {
2163 Objects.requireNonNull(name);
2164 Method method = getMethod0(name, parameterTypes);
2165 if (method == null) {
2166 throw new NoSuchMethodException(methodToString(name, parameterTypes));
2167 }
2168 return getReflectionFactory().copyMethod(method);
2169 }
2170
2171 /**
2172 * Returns a {@code Constructor} object that reflects the specified
2173 * public constructor of the class represented by this {@code Class}
2174 * object. The {@code parameterTypes} parameter is an array of
2175 * {@code Class} objects that identify the constructor's formal
2176 * parameter types, in declared order.
2177 *
2178 * If this {@code Class} object represents an inner class
2179 * declared in a non-static context, the formal parameter types
2180 * include the explicit enclosing instance as the first parameter.
2181 *
2182 * <p> The constructor to reflect is the public constructor of the class
2183 * represented by this {@code Class} object whose formal parameter
2184 * types match those specified by {@code parameterTypes}.
2185 *
2186 * @param parameterTypes the parameter array
2187 * @return the {@code Constructor} object of the public constructor that
2188 * matches the specified {@code parameterTypes}
2189 * @throws NoSuchMethodException if a matching constructor is not found,
2190 * including when this {@code Class} object represents
2191 * an interface, a primitive type, an array class, or void.
2192 *
2193 * @see #getDeclaredConstructor(Class[])
2194 * @since 1.1
2195 */
2196 public Constructor<T> getConstructor(Class<?>... parameterTypes)
2197 throws NoSuchMethodException {
2198 return getReflectionFactory().copyConstructor(
2199 getConstructor0(parameterTypes, Member.PUBLIC));
2200 }
2201
2202
2203 /**
2204 * Returns an array of {@code Class} objects reflecting all the
2205 * classes and interfaces declared as members of the class represented by
2206 * this {@code Class} object. This includes public, protected, default
2207 * (package) access, and private classes and interfaces declared by the
2208 * class, but excludes inherited classes and interfaces. This method
2209 * returns an array of length 0 if the class declares no classes or
2210 * interfaces as members, or if this {@code Class} object represents a
2211 * primitive type, an array class, or void.
2212 *
2213 * @return the array of {@code Class} objects representing all the
2214 * declared members of this class
2215 *
2216 * @since 1.1
2217 * @jls 8.5 Member Class and Interface Declarations
2218 */
2219 public Class<?>[] getDeclaredClasses() {
2220 return getDeclaredClasses0();
2221 }
2222
2223
2224 /**
2225 * Returns an array of {@code Field} objects reflecting all the fields
2226 * declared by the class or interface represented by this
2227 * {@code Class} object. This includes public, protected, default
2228 * (package) access, and private fields, but excludes inherited fields.
2229 *
2230 * <p> If this {@code Class} object represents a class or interface with no
2231 * declared fields, then this method returns an array of length 0.
2232 *
2233 * <p> If this {@code Class} object represents an array type, a primitive
2234 * type, or void, then this method returns an array of length 0.
2235 *
2236 * <p> The elements in the returned array are not sorted and are not in any
2237 * particular order.
2238 *
2239 * @return the array of {@code Field} objects representing all the
2240 * declared fields of this class
2241 *
2242 * @since 1.1
2243 * @jls 8.2 Class Members
2244 * @jls 8.3 Field Declarations
2245 */
2246 public Field[] getDeclaredFields() {
2247 return copyFields(privateGetDeclaredFields(false));
2248 }
2249
2250 /**
2251 * Returns an array of {@code RecordComponent} objects representing all the
2252 * record components of this record class, or {@code null} if this class is
2253 * not a record class.
2254 *
2255 * <p> The components are returned in the same order that they are declared
2256 * in the record header. The array is empty if this record class has no
2257 * components. If the class is not a record class, that is {@link
2258 * #isRecord()} returns {@code false}, then this method returns {@code null}.
2259 * Conversely, if {@link #isRecord()} returns {@code true}, then this method
2260 * returns a non-null value.
2261 *
2262 * @apiNote
2263 * <p> The following method can be used to find the record canonical constructor:
2264 *
2265 * {@snippet lang="java" :
2266 * static <T extends Record> Constructor<T> getCanonicalConstructor(Class<T> cls)
2267 * throws NoSuchMethodException {
2268 * Class<?>[] paramTypes =
2269 * Arrays.stream(cls.getRecordComponents())
2270 * .map(RecordComponent::getType)
2271 * .toArray(Class<?>[]::new);
2272 * return cls.getDeclaredConstructor(paramTypes);
2273 * }}
2274 *
2275 * @return An array of {@code RecordComponent} objects representing all the
2276 * record components of this record class, or {@code null} if this
2277 * class is not a record class
2278 *
2279 * @jls 8.10 Record Classes
2280 * @since 16
2281 */
2282 public RecordComponent[] getRecordComponents() {
2283 if (!isRecord()) {
2284 return null;
2285 }
2286 return getRecordComponents0();
2287 }
2288
2289 /**
2290 * Returns an array containing {@code Method} objects reflecting all the
2291 * declared methods of the class or interface represented by this {@code
2292 * Class} object, including public, protected, default (package)
2293 * access, and private methods, but excluding inherited methods.
2294 * The declared methods may include methods <em>not</em> in the
2295 * source of the class or interface, including {@linkplain
2296 * Method#isBridge bridge methods} and other {@linkplain
2297 * Executable#isSynthetic synthetic} methods added by compilers.
2298 *
2299 * <p> If this {@code Class} object represents a class or interface that
2300 * has multiple declared methods with the same name and parameter types,
2301 * but different return types, then the returned array has a {@code Method}
2302 * object for each such method.
2303 *
2304 * <p> If this {@code Class} object represents a class or interface that
2305 * has a class initialization method {@value ConstantDescs#CLASS_INIT_NAME},
2306 * then the returned array does <em>not</em> have a corresponding {@code
2307 * Method} object.
2308 *
2309 * <p> If this {@code Class} object represents a class or interface with no
2310 * declared methods, then the returned array has length 0.
2311 *
2312 * <p> If this {@code Class} object represents an array type, a primitive
2313 * type, or void, then the returned array has length 0.
2314 *
2315 * <p> The elements in the returned array are not sorted and are not in any
2316 * particular order.
2317 *
2318 * @return the array of {@code Method} objects representing all the
2319 * declared methods of this class
2320 *
2321 * @jls 8.2 Class Members
2322 * @jls 8.4 Method Declarations
2323 * @see <a
2324 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
2325 * programming language and JVM modeling in core reflection</a>
2326 * @since 1.1
2327 */
2328 public Method[] getDeclaredMethods() {
2329 return copyMethods(privateGetDeclaredMethods(false));
2330 }
2331
2332 /**
2333 * Returns an array of {@code Constructor} objects reflecting all the
2334 * constructors implicitly or explicitly declared by the class represented by this
2335 * {@code Class} object. These are public, protected, default
2336 * (package) access, and private constructors. The elements in the array
2337 * returned are not sorted and are not in any particular order. If the
2338 * class has a default constructor (JLS {@jls 8.8.9}), it is included in the returned array.
2339 * If a record class has a canonical constructor (JLS {@jls
2340 * 8.10.4.1}, {@jls 8.10.4.2}), it is included in the returned array.
2341 *
2342 * This method returns an array of length 0 if this {@code Class}
2343 * object represents an interface, a primitive type, an array class, or
2344 * void.
2345 *
2346 * @return the array of {@code Constructor} objects representing all the
2347 * declared constructors of this class
2348 *
2349 * @since 1.1
2350 * @see #getConstructors()
2351 * @jls 8.8 Constructor Declarations
2352 */
2353 public Constructor<?>[] getDeclaredConstructors() {
2354 return copyConstructors(privateGetDeclaredConstructors(false));
2355 }
2356
2357
2358 /**
2359 * Returns a {@code Field} object that reflects the specified declared
2360 * field of the class or interface represented by this {@code Class}
2361 * object. The {@code name} parameter is a {@code String} that specifies
2362 * the simple name of the desired field.
2363 *
2364 * <p> If this {@code Class} object represents an array type, then this
2365 * method does not find the {@code length} field of the array type.
2366 *
2367 * @param name the name of the field
2368 * @return the {@code Field} object for the specified field in this
2369 * class
2370 * @throws NoSuchFieldException if a field with the specified name is
2371 * not found.
2372 * @throws NullPointerException if {@code name} is {@code null}
2373 *
2374 * @since 1.1
2375 * @jls 8.2 Class Members
2376 * @jls 8.3 Field Declarations
2377 */
2378 public Field getDeclaredField(String name) throws NoSuchFieldException {
2379 Objects.requireNonNull(name);
2380 Field field = searchFields(privateGetDeclaredFields(false), name);
2381 if (field == null) {
2382 throw new NoSuchFieldException(name);
2383 }
2384 return getReflectionFactory().copyField(field);
2385 }
2386
2387
2388 /**
2389 * Returns a {@code Method} object that reflects the specified
2390 * declared method of the class or interface represented by this
2391 * {@code Class} object. The {@code name} parameter is a
2392 * {@code String} that specifies the simple name of the desired
2393 * method, and the {@code parameterTypes} parameter is an array of
2394 * {@code Class} objects that identify the method's formal parameter
2395 * types, in declared order. If more than one method with the same
2396 * parameter types is declared in a class, and one of these methods has a
2397 * return type that is more specific than any of the others, that method is
2398 * returned; otherwise one of the methods is chosen arbitrarily. If the
2399 * name is {@value ConstantDescs#INIT_NAME} or {@value
2400 * ConstantDescs#CLASS_INIT_NAME} a {@code NoSuchMethodException}
2401 * is raised.
2402 *
2403 * <p> If this {@code Class} object represents an array type, then this
2404 * method does not find the {@code clone()} method.
2405 *
2406 * @param name the name of the method
2407 * @param parameterTypes the parameter array
2408 * @return the {@code Method} object for the method of this class
2409 * matching the specified name and parameters
2410 * @throws NoSuchMethodException if a matching method is not found.
2411 * @throws NullPointerException if {@code name} is {@code null}
2412 *
2413 * @jls 8.2 Class Members
2414 * @jls 8.4 Method Declarations
2415 * @since 1.1
2416 */
2417 public Method getDeclaredMethod(String name, Class<?>... parameterTypes)
2418 throws NoSuchMethodException {
2419 Objects.requireNonNull(name);
2420 Method method = searchMethods(privateGetDeclaredMethods(false), name, parameterTypes);
2421 if (method == null) {
2422 throw new NoSuchMethodException(methodToString(name, parameterTypes));
2423 }
2424 return getReflectionFactory().copyMethod(method);
2425 }
2426
2427 /**
2428 * Returns the list of {@code Method} objects for the declared public
2429 * methods of this class or interface that have the specified method name
2430 * and parameter types.
2431 *
2432 * @param name the name of the method
2433 * @param parameterTypes the parameter array
2434 * @return the list of {@code Method} objects for the public methods of
2435 * this class matching the specified name and parameters
2436 */
2437 List<Method> getDeclaredPublicMethods(String name, Class<?>... parameterTypes) {
2438 Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true);
2439 ReflectionFactory factory = getReflectionFactory();
2440 List<Method> result = new ArrayList<>();
2441 for (Method method : methods) {
2442 if (method.getName().equals(name)
2443 && Arrays.equals(
2444 factory.getExecutableSharedParameterTypes(method),
2445 parameterTypes)) {
2446 result.add(factory.copyMethod(method));
2447 }
2448 }
2449 return result;
2450 }
2451
2452 /**
2453 * Returns the most specific {@code Method} object of this class, super class or
2454 * interface that have the specified method name and parameter types.
2455 *
2456 * @param publicOnly true if only public methods are examined, otherwise all methods
2457 * @param name the name of the method
2458 * @param parameterTypes the parameter array
2459 * @return the {@code Method} object for the method found from this class matching
2460 * the specified name and parameters, or null if not found
2461 */
2462 Method findMethod(boolean publicOnly, String name, Class<?>... parameterTypes) {
2463 PublicMethods.MethodList res = getMethodsRecursive(name, parameterTypes, true, publicOnly);
2464 return res == null ? null : getReflectionFactory().copyMethod(res.getMostSpecific());
2465 }
2466
2467 /**
2468 * Returns a {@code Constructor} object that reflects the specified
2469 * constructor of the class represented by this
2470 * {@code Class} object. The {@code parameterTypes} parameter is
2471 * an array of {@code Class} objects that identify the constructor's
2472 * formal parameter types, in declared order.
2473 *
2474 * If this {@code Class} object represents an inner class
2475 * declared in a non-static context, the formal parameter types
2476 * include the explicit enclosing instance as the first parameter.
2477 *
2478 * @param parameterTypes the parameter array
2479 * @return The {@code Constructor} object for the constructor with the
2480 * specified parameter list
2481 * @throws NoSuchMethodException if a matching constructor is not found,
2482 * including when this {@code Class} object represents
2483 * an interface, a primitive type, an array class, or void.
2484 *
2485 * @see #getConstructor(Class[])
2486 * @since 1.1
2487 */
2488 public Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes)
2489 throws NoSuchMethodException {
2490 return getReflectionFactory().copyConstructor(
2491 getConstructor0(parameterTypes, Member.DECLARED));
2492 }
2493
2494 /**
2495 * Finds a resource with a given name.
2496 *
2497 * <p> If this class is in a named {@link Module Module} then this method
2498 * will attempt to find the resource in the module. This is done by
2499 * delegating to the module's class loader {@link
2500 * ClassLoader#findResource(String,String) findResource(String,String)}
2501 * method, invoking it with the module name and the absolute name of the
2502 * resource. Resources in named modules are subject to the rules for
2503 * encapsulation specified in the {@code Module} {@link
2504 * Module#getResourceAsStream getResourceAsStream} method and so this
2505 * method returns {@code null} when the resource is a
2506 * non-"{@code .class}" resource in a package that is not open to the
2507 * caller's module.
2508 *
2509 * <p> Otherwise, if this class is not in a named module then the rules for
2510 * searching resources associated with a given class are implemented by the
2511 * defining {@linkplain ClassLoader class loader} of the class. This method
2512 * delegates to this {@code Class} object's class loader.
2513 * If this {@code Class} object was loaded by the bootstrap class loader,
2514 * the method delegates to {@link ClassLoader#getSystemResourceAsStream}.
2515 *
2516 * <p> Before delegation, an absolute resource name is constructed from the
2517 * given resource name using this algorithm:
2518 *
2519 * <ul>
2520 *
2521 * <li> If the {@code name} begins with a {@code '/'}
2522 * (<code>'\u002f'</code>), then the absolute name of the resource is the
2523 * portion of the {@code name} following the {@code '/'}.
2524 *
2525 * <li> Otherwise, the absolute name is of the following form:
2526 *
2527 * <blockquote>
2528 * {@code modified_package_name/name}
2529 * </blockquote>
2530 *
2531 * <p> Where the {@code modified_package_name} is the package name of this
2532 * object with {@code '/'} substituted for {@code '.'}
2533 * (<code>'\u002e'</code>).
2534 *
2535 * </ul>
2536 *
2537 * @param name name of the desired resource
2538 * @return A {@link java.io.InputStream} object; {@code null} if no
2539 * resource with this name is found, or the resource is in a package
2540 * that is not {@linkplain Module#isOpen(String, Module) open} to at
2541 * least the caller module.
2542 * @throws NullPointerException If {@code name} is {@code null}
2543 *
2544 * @see Module#getResourceAsStream(String)
2545 * @since 1.1
2546 */
2547 @CallerSensitive
2548 public InputStream getResourceAsStream(String name) {
2549 name = resolveName(name);
2550
2551 Module thisModule = getModule();
2552 if (thisModule.isNamed()) {
2553 // check if resource can be located by caller
2554 if (Resources.canEncapsulate(name)
2555 && !isOpenToCaller(name, Reflection.getCallerClass())) {
2556 return null;
2557 }
2558
2559 // resource not encapsulated or in package open to caller
2560 String mn = thisModule.getName();
2561 ClassLoader cl = classLoader;
2562 try {
2563
2564 // special-case built-in class loaders to avoid the
2565 // need for a URL connection
2566 if (cl == null) {
2567 return BootLoader.findResourceAsStream(mn, name);
2568 } else if (cl instanceof BuiltinClassLoader bcl) {
2569 return bcl.findResourceAsStream(mn, name);
2570 } else {
2571 URL url = cl.findResource(mn, name);
2572 return (url != null) ? url.openStream() : null;
2573 }
2574
2575 } catch (IOException | SecurityException e) {
2576 return null;
2577 }
2578 }
2579
2580 // unnamed module
2581 ClassLoader cl = classLoader;
2582 if (cl == null) {
2583 return ClassLoader.getSystemResourceAsStream(name);
2584 } else {
2585 return cl.getResourceAsStream(name);
2586 }
2587 }
2588
2589 /**
2590 * Finds a resource with a given name.
2591 *
2592 * <p> If this class is in a named {@link Module Module} then this method
2593 * will attempt to find the resource in the module. This is done by
2594 * delegating to the module's class loader {@link
2595 * ClassLoader#findResource(String,String) findResource(String,String)}
2596 * method, invoking it with the module name and the absolute name of the
2597 * resource. Resources in named modules are subject to the rules for
2598 * encapsulation specified in the {@code Module} {@link
2599 * Module#getResourceAsStream getResourceAsStream} method and so this
2600 * method returns {@code null} when the resource is a
2601 * non-"{@code .class}" resource in a package that is not open to the
2602 * caller's module.
2603 *
2604 * <p> Otherwise, if this class is not in a named module then the rules for
2605 * searching resources associated with a given class are implemented by the
2606 * defining {@linkplain ClassLoader class loader} of the class. This method
2607 * delegates to this {@code Class} object's class loader.
2608 * If this {@code Class} object was loaded by the bootstrap class loader,
2609 * the method delegates to {@link ClassLoader#getSystemResource}.
2610 *
2611 * <p> Before delegation, an absolute resource name is constructed from the
2612 * given resource name using this algorithm:
2613 *
2614 * <ul>
2615 *
2616 * <li> If the {@code name} begins with a {@code '/'}
2617 * (<code>'\u002f'</code>), then the absolute name of the resource is the
2618 * portion of the {@code name} following the {@code '/'}.
2619 *
2620 * <li> Otherwise, the absolute name is of the following form:
2621 *
2622 * <blockquote>
2623 * {@code modified_package_name/name}
2624 * </blockquote>
2625 *
2626 * <p> Where the {@code modified_package_name} is the package name of this
2627 * object with {@code '/'} substituted for {@code '.'}
2628 * (<code>'\u002e'</code>).
2629 *
2630 * </ul>
2631 *
2632 * @param name name of the desired resource
2633 * @return A {@link java.net.URL} object; {@code null} if no resource with
2634 * this name is found, the resource cannot be located by a URL, or the
2635 * resource is in a package that is not
2636 * {@linkplain Module#isOpen(String, Module) open} to at least the caller
2637 * module.
2638 * @throws NullPointerException If {@code name} is {@code null}
2639 * @since 1.1
2640 */
2641 @CallerSensitive
2642 public URL getResource(String name) {
2643 name = resolveName(name);
2644
2645 Module thisModule = getModule();
2646 if (thisModule.isNamed()) {
2647 // check if resource can be located by caller
2648 if (Resources.canEncapsulate(name)
2649 && !isOpenToCaller(name, Reflection.getCallerClass())) {
2650 return null;
2651 }
2652
2653 // resource not encapsulated or in package open to caller
2654 String mn = thisModule.getName();
2655 ClassLoader cl = classLoader;
2656 try {
2657 if (cl == null) {
2658 return BootLoader.findResource(mn, name);
2659 } else {
2660 return cl.findResource(mn, name);
2661 }
2662 } catch (IOException ioe) {
2663 return null;
2664 }
2665 }
2666
2667 // unnamed module
2668 ClassLoader cl = classLoader;
2669 if (cl == null) {
2670 return ClassLoader.getSystemResource(name);
2671 } else {
2672 return cl.getResource(name);
2673 }
2674 }
2675
2676 /**
2677 * Returns true if a resource with the given name can be located by the
2678 * given caller. All resources in a module can be located by code in
2679 * the module. For other callers, then the package needs to be open to
2680 * the caller.
2681 */
2682 private boolean isOpenToCaller(String name, Class<?> caller) {
2683 // assert getModule().isNamed();
2684 Module thisModule = getModule();
2685 Module callerModule = (caller != null) ? caller.getModule() : null;
2686 if (callerModule != thisModule) {
2687 String pn = Resources.toPackageName(name);
2688 if (thisModule.getDescriptor().packages().contains(pn)) {
2689 if (callerModule == null) {
2690 // no caller, return true if the package is open to all modules
2691 return thisModule.isOpen(pn);
2692 }
2693 if (!thisModule.isOpen(pn, callerModule)) {
2694 // package not open to caller
2695 return false;
2696 }
2697 }
2698 }
2699 return true;
2700 }
2701
2702 private transient final ProtectionDomain protectionDomain;
2703
2704 /** Holder for the protection domain returned when the internal domain is null */
2705 private static class Holder {
2706 private static final ProtectionDomain allPermDomain;
2707 static {
2708 Permissions perms = new Permissions();
2709 perms.add(new AllPermission());
2710 allPermDomain = new ProtectionDomain(null, perms);
2711 }
2712 }
2713
2714 /**
2715 * Returns the {@code ProtectionDomain} of this class.
2716 *
2717 * @return the ProtectionDomain of this class
2718 *
2719 * @see java.security.ProtectionDomain
2720 * @since 1.2
2721 */
2722 public ProtectionDomain getProtectionDomain() {
2723 if (protectionDomain == null) {
2724 return Holder.allPermDomain;
2725 } else {
2726 return protectionDomain;
2727 }
2728 }
2729
2730 /*
2731 * Returns the Class object for the named primitive type. Type parameter T
2732 * avoids redundant casts for trusted code.
2733 */
2734 static native <T> Class<T> getPrimitiveClass(String name);
2735
2736 /**
2737 * Add a package name prefix if the name is not absolute. Remove leading "/"
2738 * if name is absolute
2739 */
2740 private String resolveName(String name) {
2741 if (!name.startsWith("/")) {
2742 String baseName = getPackageName();
2743 if (!baseName.isEmpty()) {
2744 int len = baseName.length() + 1 + name.length();
2745 StringBuilder sb = new StringBuilder(len);
2746 name = sb.append(baseName.replace('.', '/'))
2747 .append('/')
2748 .append(name)
2749 .toString();
2750 }
2751 } else {
2752 name = name.substring(1);
2753 }
2754 return name;
2755 }
2756
2757 /**
2758 * Atomic operations support.
2759 */
2760 private static class Atomic {
2761 // initialize Unsafe machinery here, since we need to call Class.class instance method
2762 // and have to avoid calling it in the static initializer of the Class class...
2763 private static final Unsafe unsafe = Unsafe.getUnsafe();
2764 // offset of Class.reflectionData instance field
2765 private static final long reflectionDataOffset
2766 = unsafe.objectFieldOffset(Class.class, "reflectionData");
2767 // offset of Class.annotationType instance field
2768 private static final long annotationTypeOffset
2769 = unsafe.objectFieldOffset(Class.class, "annotationType");
2770 // offset of Class.annotationData instance field
2771 private static final long annotationDataOffset
2772 = unsafe.objectFieldOffset(Class.class, "annotationData");
2773
2774 static <T> boolean casReflectionData(Class<?> clazz,
2775 SoftReference<ReflectionData<T>> oldData,
2776 SoftReference<ReflectionData<T>> newData) {
2777 return unsafe.compareAndSetReference(clazz, reflectionDataOffset, oldData, newData);
2778 }
2779
2780 static boolean casAnnotationType(Class<?> clazz,
2781 AnnotationType oldType,
2782 AnnotationType newType) {
2783 return unsafe.compareAndSetReference(clazz, annotationTypeOffset, oldType, newType);
2784 }
2785
2786 static boolean casAnnotationData(Class<?> clazz,
2787 AnnotationData oldData,
2788 AnnotationData newData) {
2789 return unsafe.compareAndSetReference(clazz, annotationDataOffset, oldData, newData);
2790 }
2791 }
2792
2793 /**
2794 * Reflection support.
2795 */
2796
2797 // Reflection data caches various derived names and reflective members. Cached
2798 // values may be invalidated when JVM TI RedefineClasses() is called
2799 private static class ReflectionData<T> {
2800 volatile Field[] declaredFields;
2801 volatile Field[] publicFields;
2802 volatile Method[] declaredMethods;
2803 volatile Method[] publicMethods;
2804 volatile Constructor<T>[] declaredConstructors;
2805 volatile Constructor<T>[] publicConstructors;
2806 // Intermediate results for getFields and getMethods
2807 volatile Field[] declaredPublicFields;
2808 volatile Method[] declaredPublicMethods;
2809 volatile Class<?>[] interfaces;
2810
2811 // Cached names
2812 String simpleName;
2813 String canonicalName;
2814 static final String NULL_SENTINEL = new String();
2815
2816 // Value of classRedefinedCount when we created this ReflectionData instance
2817 final int redefinedCount;
2818
2819 ReflectionData(int redefinedCount) {
2820 this.redefinedCount = redefinedCount;
2821 }
2822 }
2823
2824 private transient volatile SoftReference<ReflectionData<T>> reflectionData;
2825
2826 // Incremented by the VM on each call to JVM TI RedefineClasses()
2827 // that redefines this class or a superclass.
2828 private transient volatile int classRedefinedCount;
2829
2830 // Lazily create and cache ReflectionData
2831 private ReflectionData<T> reflectionData() {
2832 SoftReference<ReflectionData<T>> reflectionData = this.reflectionData;
2833 int classRedefinedCount = this.classRedefinedCount;
2834 ReflectionData<T> rd;
2835 if (reflectionData != null &&
2836 (rd = reflectionData.get()) != null &&
2837 rd.redefinedCount == classRedefinedCount) {
2838 return rd;
2839 }
2840 // else no SoftReference or cleared SoftReference or stale ReflectionData
2841 // -> create and replace new instance
2842 return newReflectionData(reflectionData, classRedefinedCount);
2843 }
2844
2845 private ReflectionData<T> newReflectionData(SoftReference<ReflectionData<T>> oldReflectionData,
2846 int classRedefinedCount) {
2847 while (true) {
2848 ReflectionData<T> rd = new ReflectionData<>(classRedefinedCount);
2849 // try to CAS it...
2850 if (Atomic.casReflectionData(this, oldReflectionData, new SoftReference<>(rd))) {
2851 return rd;
2852 }
2853 // else retry
2854 oldReflectionData = this.reflectionData;
2855 classRedefinedCount = this.classRedefinedCount;
2856 if (oldReflectionData != null &&
2857 (rd = oldReflectionData.get()) != null &&
2858 rd.redefinedCount == classRedefinedCount) {
2859 return rd;
2860 }
2861 }
2862 }
2863
2864 // Generic signature handling
2865 private native String getGenericSignature0();
2866
2867 // Generic info repository; lazily initialized
2868 private transient volatile ClassRepository genericInfo;
2869
2870 // accessor for factory
2871 private GenericsFactory getFactory() {
2872 // create scope and factory
2873 return CoreReflectionFactory.make(this, ClassScope.make(this));
2874 }
2875
2876 // accessor for generic info repository;
2877 // generic info is lazily initialized
2878 private ClassRepository getGenericInfo() {
2879 ClassRepository genericInfo = this.genericInfo;
2880 if (genericInfo == null) {
2881 String signature = getGenericSignature0();
2882 if (signature == null) {
2883 genericInfo = ClassRepository.NONE;
2884 } else {
2885 genericInfo = ClassRepository.make(signature, getFactory());
2886 }
2887 this.genericInfo = genericInfo;
2888 }
2889 return (genericInfo != ClassRepository.NONE) ? genericInfo : null;
2890 }
2891
2892 // Annotations handling
2893 native byte[] getRawAnnotations();
2894 // Since 1.8
2895 native byte[] getRawTypeAnnotations();
2896 static byte[] getExecutableTypeAnnotationBytes(Executable ex) {
2897 return getReflectionFactory().getExecutableTypeAnnotationBytes(ex);
2898 }
2899
2900 native ConstantPool getConstantPool();
2901
2902 //
2903 //
2904 // java.lang.reflect.Field handling
2905 //
2906 //
2907
2908 // Returns an array of "root" fields. These Field objects must NOT
2909 // be propagated to the outside world, but must instead be copied
2910 // via ReflectionFactory.copyField.
2911 private Field[] privateGetDeclaredFields(boolean publicOnly) {
2912 Field[] res;
2913 ReflectionData<T> rd = reflectionData();
2914 res = publicOnly ? rd.declaredPublicFields : rd.declaredFields;
2915 if (res != null) return res;
2916 // No cached value available; request value from VM
2917 res = Reflection.filterFields(this, getDeclaredFields0(publicOnly));
2918 if (publicOnly) {
2919 rd.declaredPublicFields = res;
2920 } else {
2921 rd.declaredFields = res;
2922 }
2923 return res;
2924 }
2925
2926 // Returns an array of "root" fields. These Field objects must NOT
2927 // be propagated to the outside world, but must instead be copied
2928 // via ReflectionFactory.copyField.
2929 private Field[] privateGetPublicFields() {
2930 Field[] res;
2931 ReflectionData<T> rd = reflectionData();
2932 res = rd.publicFields;
2933 if (res != null) return res;
2934
2935 // Use a linked hash set to ensure order is preserved and
2936 // fields from common super interfaces are not duplicated
2937 LinkedHashSet<Field> fields = new LinkedHashSet<>();
2938
2939 // Local fields
2940 addAll(fields, privateGetDeclaredFields(true));
2941
2942 // Direct superinterfaces, recursively
2943 for (Class<?> si : getInterfaces(/* cloneArray */ false)) {
2944 addAll(fields, si.privateGetPublicFields());
2945 }
2946
2947 // Direct superclass, recursively
2948 Class<?> sc = getSuperclass();
2949 if (sc != null) {
2950 addAll(fields, sc.privateGetPublicFields());
2951 }
2952
2953 res = fields.toArray(new Field[0]);
2954 rd.publicFields = res;
2955 return res;
2956 }
2957
2958 private static void addAll(Collection<Field> c, Field[] o) {
2959 for (Field f : o) {
2960 c.add(f);
2961 }
2962 }
2963
2964
2965 //
2966 //
2967 // java.lang.reflect.Constructor handling
2968 //
2969 //
2970
2971 // Returns an array of "root" constructors. These Constructor
2972 // objects must NOT be propagated to the outside world, but must
2973 // instead be copied via ReflectionFactory.copyConstructor.
2974 private Constructor<T>[] privateGetDeclaredConstructors(boolean publicOnly) {
2975 Constructor<T>[] res;
2976 ReflectionData<T> rd = reflectionData();
2977 res = publicOnly ? rd.publicConstructors : rd.declaredConstructors;
2978 if (res != null) return res;
2979 // No cached value available; request value from VM
2980 if (isInterface()) {
2981 @SuppressWarnings("unchecked")
2982 Constructor<T>[] temporaryRes = (Constructor<T>[]) new Constructor<?>[0];
2983 res = temporaryRes;
2984 } else {
2985 res = getDeclaredConstructors0(publicOnly);
2986 }
2987 if (publicOnly) {
2988 rd.publicConstructors = res;
2989 } else {
2990 rd.declaredConstructors = res;
2991 }
2992 return res;
2993 }
2994
2995 //
2996 //
2997 // java.lang.reflect.Method handling
2998 //
2999 //
3000
3001 // Returns an array of "root" methods. These Method objects must NOT
3002 // be propagated to the outside world, but must instead be copied
3003 // via ReflectionFactory.copyMethod.
3004 private Method[] privateGetDeclaredMethods(boolean publicOnly) {
3005 Method[] res;
3006 ReflectionData<T> rd = reflectionData();
3007 res = publicOnly ? rd.declaredPublicMethods : rd.declaredMethods;
3008 if (res != null) return res;
3009 // No cached value available; request value from VM
3010 res = Reflection.filterMethods(this, getDeclaredMethods0(publicOnly));
3011 if (publicOnly) {
3012 rd.declaredPublicMethods = res;
3013 } else {
3014 rd.declaredMethods = res;
3015 }
3016 return res;
3017 }
3018
3019 // Returns an array of "root" methods. These Method objects must NOT
3020 // be propagated to the outside world, but must instead be copied
3021 // via ReflectionFactory.copyMethod.
3022 private Method[] privateGetPublicMethods() {
3023 Method[] res;
3024 ReflectionData<T> rd = reflectionData();
3025 res = rd.publicMethods;
3026 if (res != null) return res;
3027
3028 // No cached value available; compute value recursively.
3029 // Start by fetching public declared methods...
3030 PublicMethods pms = new PublicMethods();
3031 for (Method m : privateGetDeclaredMethods(/* publicOnly */ true)) {
3032 pms.merge(m);
3033 }
3034 // ...then recur over superclass methods...
3035 Class<?> sc = getSuperclass();
3036 if (sc != null) {
3037 for (Method m : sc.privateGetPublicMethods()) {
3038 pms.merge(m);
3039 }
3040 }
3041 // ...and finally over direct superinterfaces.
3042 for (Class<?> intf : getInterfaces(/* cloneArray */ false)) {
3043 for (Method m : intf.privateGetPublicMethods()) {
3044 // static interface methods are not inherited
3045 if (!Modifier.isStatic(m.getModifiers())) {
3046 pms.merge(m);
3047 }
3048 }
3049 }
3050
3051 res = pms.toArray();
3052 rd.publicMethods = res;
3053 return res;
3054 }
3055
3056
3057 //
3058 // Helpers for fetchers of one field, method, or constructor
3059 //
3060
3061 // This method does not copy the returned Field object!
3062 private static Field searchFields(Field[] fields, String name) {
3063 for (Field field : fields) {
3064 if (field.getName().equals(name)) {
3065 return field;
3066 }
3067 }
3068 return null;
3069 }
3070
3071 // Returns a "root" Field object. This Field object must NOT
3072 // be propagated to the outside world, but must instead be copied
3073 // via ReflectionFactory.copyField.
3074 private Field getField0(String name) {
3075 // Note: the intent is that the search algorithm this routine
3076 // uses be equivalent to the ordering imposed by
3077 // privateGetPublicFields(). It fetches only the declared
3078 // public fields for each class, however, to reduce the number
3079 // of Field objects which have to be created for the common
3080 // case where the field being requested is declared in the
3081 // class which is being queried.
3082 Field res;
3083 // Search declared public fields
3084 if ((res = searchFields(privateGetDeclaredFields(true), name)) != null) {
3085 return res;
3086 }
3087 // Direct superinterfaces, recursively
3088 Class<?>[] interfaces = getInterfaces(/* cloneArray */ false);
3089 for (Class<?> c : interfaces) {
3090 if ((res = c.getField0(name)) != null) {
3091 return res;
3092 }
3093 }
3094 // Direct superclass, recursively
3095 if (!isInterface()) {
3096 Class<?> c = getSuperclass();
3097 if (c != null) {
3098 if ((res = c.getField0(name)) != null) {
3099 return res;
3100 }
3101 }
3102 }
3103 return null;
3104 }
3105
3106 // This method does not copy the returned Method object!
3107 private static Method searchMethods(Method[] methods,
3108 String name,
3109 Class<?>[] parameterTypes)
3110 {
3111 ReflectionFactory fact = getReflectionFactory();
3112 Method res = null;
3113 for (Method m : methods) {
3114 if (m.getName().equals(name)
3115 && arrayContentsEq(parameterTypes,
3116 fact.getExecutableSharedParameterTypes(m))
3117 && (res == null
3118 || (res.getReturnType() != m.getReturnType()
3119 && res.getReturnType().isAssignableFrom(m.getReturnType()))))
3120 res = m;
3121 }
3122 return res;
3123 }
3124
3125 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
3126
3127 // Returns a "root" Method object. This Method object must NOT
3128 // be propagated to the outside world, but must instead be copied
3129 // via ReflectionFactory.copyMethod.
3130 private Method getMethod0(String name, Class<?>[] parameterTypes) {
3131 PublicMethods.MethodList res = getMethodsRecursive(
3132 name,
3133 parameterTypes == null ? EMPTY_CLASS_ARRAY : parameterTypes,
3134 /* includeStatic */ true, /* publicOnly */ true);
3135 return res == null ? null : res.getMostSpecific();
3136 }
3137
3138 // Returns a list of "root" Method objects. These Method objects must NOT
3139 // be propagated to the outside world, but must instead be copied
3140 // via ReflectionFactory.copyMethod.
3141 private PublicMethods.MethodList getMethodsRecursive(String name,
3142 Class<?>[] parameterTypes,
3143 boolean includeStatic,
3144 boolean publicOnly) {
3145 // 1st check declared methods
3146 Method[] methods = privateGetDeclaredMethods(publicOnly);
3147 PublicMethods.MethodList res = PublicMethods.MethodList
3148 .filter(methods, name, parameterTypes, includeStatic);
3149 // if there is at least one match among declared methods, we need not
3150 // search any further as such match surely overrides matching methods
3151 // declared in superclass(es) or interface(s).
3152 if (res != null) {
3153 return res;
3154 }
3155
3156 // if there was no match among declared methods,
3157 // we must consult the superclass (if any) recursively...
3158 Class<?> sc = getSuperclass();
3159 if (sc != null) {
3160 res = sc.getMethodsRecursive(name, parameterTypes, includeStatic, publicOnly);
3161 }
3162
3163 // ...and coalesce the superclass methods with methods obtained
3164 // from directly implemented interfaces excluding static methods...
3165 for (Class<?> intf : getInterfaces(/* cloneArray */ false)) {
3166 res = PublicMethods.MethodList.merge(
3167 res, intf.getMethodsRecursive(name, parameterTypes, /* includeStatic */ false, publicOnly));
3168 }
3169
3170 return res;
3171 }
3172
3173 // Returns a "root" Constructor object. This Constructor object must NOT
3174 // be propagated to the outside world, but must instead be copied
3175 // via ReflectionFactory.copyConstructor.
3176 private Constructor<T> getConstructor0(Class<?>[] parameterTypes,
3177 int which) throws NoSuchMethodException
3178 {
3179 ReflectionFactory fact = getReflectionFactory();
3180 Constructor<T>[] constructors = privateGetDeclaredConstructors((which == Member.PUBLIC));
3181 for (Constructor<T> constructor : constructors) {
3182 if (arrayContentsEq(parameterTypes,
3183 fact.getExecutableSharedParameterTypes(constructor))) {
3184 return constructor;
3185 }
3186 }
3187 throw new NoSuchMethodException(methodToString("<init>", parameterTypes));
3188 }
3189
3190 //
3191 // Other helpers and base implementation
3192 //
3193
3194 private static boolean arrayContentsEq(Object[] a1, Object[] a2) {
3195 if (a1 == null) {
3196 return a2 == null || a2.length == 0;
3197 }
3198
3199 if (a2 == null) {
3200 return a1.length == 0;
3201 }
3202
3203 if (a1.length != a2.length) {
3204 return false;
3205 }
3206
3207 for (int i = 0; i < a1.length; i++) {
3208 if (a1[i] != a2[i]) {
3209 return false;
3210 }
3211 }
3212
3213 return true;
3214 }
3215
3216 private static Field[] copyFields(Field[] arg) {
3217 Field[] out = new Field[arg.length];
3218 ReflectionFactory fact = getReflectionFactory();
3219 for (int i = 0; i < arg.length; i++) {
3220 out[i] = fact.copyField(arg[i]);
3221 }
3222 return out;
3223 }
3224
3225 private static Method[] copyMethods(Method[] arg) {
3226 Method[] out = new Method[arg.length];
3227 ReflectionFactory fact = getReflectionFactory();
3228 for (int i = 0; i < arg.length; i++) {
3229 out[i] = fact.copyMethod(arg[i]);
3230 }
3231 return out;
3232 }
3233
3234 private static <U> Constructor<U>[] copyConstructors(Constructor<U>[] arg) {
3235 Constructor<U>[] out = arg.clone();
3236 ReflectionFactory fact = getReflectionFactory();
3237 for (int i = 0; i < out.length; i++) {
3238 out[i] = fact.copyConstructor(out[i]);
3239 }
3240 return out;
3241 }
3242
3243 private native Field[] getDeclaredFields0(boolean publicOnly);
3244 private native Method[] getDeclaredMethods0(boolean publicOnly);
3245 private native Constructor<T>[] getDeclaredConstructors0(boolean publicOnly);
3246 private native Class<?>[] getDeclaredClasses0();
3247
3248 /*
3249 * Returns an array containing the components of the Record attribute,
3250 * or null if the attribute is not present.
3251 *
3252 * Note that this method returns non-null array on a class with
3253 * the Record attribute even if this class is not a record.
3254 */
3255 private native RecordComponent[] getRecordComponents0();
3256 private native boolean isRecord0();
3257
3258 /**
3259 * Helper method to get the method name from arguments.
3260 */
3261 private String methodToString(String name, Class<?>[] argTypes) {
3262 return getName() + '.' + name +
3263 ((argTypes == null || argTypes.length == 0) ?
3264 "()" :
3265 Arrays.stream(argTypes)
3266 .map(c -> c == null ? "null" : c.getName())
3267 .collect(Collectors.joining(",", "(", ")")));
3268 }
3269
3270 /** use serialVersionUID from JDK 1.1 for interoperability */
3271 @java.io.Serial
3272 private static final long serialVersionUID = 3206093459760846163L;
3273
3274
3275 /**
3276 * Class Class is special cased within the Serialization Stream Protocol.
3277 *
3278 * A Class instance is written initially into an ObjectOutputStream in the
3279 * following format:
3280 * <pre>
3281 * {@code TC_CLASS} ClassDescriptor
3282 * A ClassDescriptor is a special cased serialization of
3283 * a {@code java.io.ObjectStreamClass} instance.
3284 * </pre>
3285 * A new handle is generated for the initial time the class descriptor
3286 * is written into the stream. Future references to the class descriptor
3287 * are written as references to the initial class descriptor instance.
3288 *
3289 * @see java.io.ObjectStreamClass
3290 */
3291 @java.io.Serial
3292 private static final ObjectStreamField[] serialPersistentFields =
3293 new ObjectStreamField[0];
3294
3295
3296 /**
3297 * Returns the assertion status that would be assigned to this
3298 * class if it were to be initialized at the time this method is invoked.
3299 * If this class has had its assertion status set, the most recent
3300 * setting will be returned; otherwise, if any package default assertion
3301 * status pertains to this class, the most recent setting for the most
3302 * specific pertinent package default assertion status is returned;
3303 * otherwise, if this class is not a system class (i.e., it has a
3304 * class loader) its class loader's default assertion status is returned;
3305 * otherwise, the system class default assertion status is returned.
3306 *
3307 * @apiNote
3308 * Few programmers will have any need for this method; it is provided
3309 * for the benefit of the JDK itself. (It allows a class to determine at
3310 * the time that it is initialized whether assertions should be enabled.)
3311 * Note that this method is not guaranteed to return the actual
3312 * assertion status that was (or will be) associated with the specified
3313 * class when it was (or will be) initialized.
3314 *
3315 * @return the desired assertion status of the specified class.
3316 * @see java.lang.ClassLoader#setClassAssertionStatus
3317 * @see java.lang.ClassLoader#setPackageAssertionStatus
3318 * @see java.lang.ClassLoader#setDefaultAssertionStatus
3319 * @since 1.4
3320 */
3321 public boolean desiredAssertionStatus() {
3322 ClassLoader loader = classLoader;
3323 // If the loader is null this is a system class, so ask the VM
3324 if (loader == null)
3325 return desiredAssertionStatus0(this);
3326
3327 // If the classloader has been initialized with the assertion
3328 // directives, ask it. Otherwise, ask the VM.
3329 synchronized(loader.assertionLock) {
3330 if (loader.classAssertionStatus != null) {
3331 return loader.desiredAssertionStatus(getName());
3332 }
3333 }
3334 return desiredAssertionStatus0(this);
3335 }
3336
3337 // Retrieves the desired assertion status of this class from the VM
3338 private static native boolean desiredAssertionStatus0(Class<?> clazz);
3339
3340 /**
3341 * Returns true if and only if this class was declared as an enum in the
3342 * source code.
3343 *
3344 * Note that {@link java.lang.Enum} is not itself an enum class.
3345 *
3346 * Also note that if an enum constant is declared with a class body,
3347 * the class of that enum constant object is an anonymous class
3348 * and <em>not</em> the class of the declaring enum class. The
3349 * {@link Enum#getDeclaringClass} method of an enum constant can
3350 * be used to get the class of the enum class declaring the
3351 * constant.
3352 *
3353 * @return true if and only if this class was declared as an enum in the
3354 * source code
3355 * @since 1.5
3356 * @jls 8.9.1 Enum Constants
3357 */
3358 public boolean isEnum() {
3359 // An enum must both directly extend java.lang.Enum and have
3360 // the ENUM bit set; classes for specialized enum constants
3361 // don't do the former.
3362 return (this.getModifiers() & ENUM) != 0 &&
3363 this.getSuperclass() == java.lang.Enum.class;
3364 }
3365
3366 /**
3367 * Returns {@code true} if and only if this class is a record class.
3368 *
3369 * <p> The {@linkplain #getSuperclass() direct superclass} of a record
3370 * class is {@code java.lang.Record}. A record class is {@linkplain
3371 * Modifier#FINAL final}. A record class has (possibly zero) record
3372 * components; {@link #getRecordComponents()} returns a non-null but
3373 * possibly empty value for a record.
3374 *
3375 * <p> Note that class {@link Record} is not a record class and thus
3376 * invoking this method on class {@code Record} returns {@code false}.
3377 *
3378 * @return true if and only if this class is a record class, otherwise false
3379 * @jls 8.10 Record Classes
3380 * @since 16
3381 */
3382 public boolean isRecord() {
3383 // this superclass and final modifier check is not strictly necessary
3384 // they are intrinsified and serve as a fast-path check
3385 return getSuperclass() == java.lang.Record.class &&
3386 (this.getModifiers() & Modifier.FINAL) != 0 &&
3387 isRecord0();
3388 }
3389
3390 // Fetches the factory for reflective objects
3391 private static ReflectionFactory getReflectionFactory() {
3392 var factory = reflectionFactory;
3393 if (factory != null) {
3394 return factory;
3395 }
3396 return reflectionFactory = ReflectionFactory.getReflectionFactory();
3397 }
3398 private static ReflectionFactory reflectionFactory;
3399
3400 /**
3401 * When CDS is enabled, the Class class may be aot-initialized. However,
3402 * we can't archive reflectionFactory, so we reset it to null, so it
3403 * will be allocated again at runtime.
3404 */
3405 private static void resetArchivedStates() {
3406 reflectionFactory = null;
3407 }
3408
3409 /**
3410 * Returns the elements of this enum class or null if this
3411 * Class object does not represent an enum class.
3412 *
3413 * @return an array containing the values comprising the enum class
3414 * represented by this {@code Class} object in the order they're
3415 * declared, or null if this {@code Class} object does not
3416 * represent an enum class
3417 * @since 1.5
3418 * @jls 8.9.1 Enum Constants
3419 */
3420 public T[] getEnumConstants() {
3421 T[] values = getEnumConstantsShared();
3422 return (values != null) ? values.clone() : null;
3423 }
3424
3425 /**
3426 * Returns the elements of this enum class or null if this
3427 * Class object does not represent an enum class;
3428 * identical to getEnumConstants except that the result is
3429 * uncloned, cached, and shared by all callers.
3430 */
3431 T[] getEnumConstantsShared() {
3432 T[] constants = enumConstants;
3433 if (constants == null) {
3434 if (!isEnum()) return null;
3435 try {
3436 final Method values = getMethod("values");
3437 values.setAccessible(true);
3438 @SuppressWarnings("unchecked")
3439 T[] temporaryConstants = (T[])values.invoke(null);
3440 enumConstants = constants = temporaryConstants;
3441 }
3442 // These can happen when users concoct enum-like classes
3443 // that don't comply with the enum spec.
3444 catch (InvocationTargetException | NoSuchMethodException |
3445 IllegalAccessException | NullPointerException |
3446 ClassCastException ex) { return null; }
3447 }
3448 return constants;
3449 }
3450 private transient volatile T[] enumConstants;
3451
3452 /**
3453 * Returns a map from simple name to enum constant. This package-private
3454 * method is used internally by Enum to implement
3455 * {@code public static <T extends Enum<T>> T valueOf(Class<T>, String)}
3456 * efficiently. Note that the map is returned by this method is
3457 * created lazily on first use. Typically it won't ever get created.
3458 */
3459 Map<String, T> enumConstantDirectory() {
3460 Map<String, T> directory = enumConstantDirectory;
3461 if (directory == null) {
3462 T[] universe = getEnumConstantsShared();
3463 if (universe == null)
3464 throw new IllegalArgumentException(
3465 getName() + " is not an enum class");
3466 directory = HashMap.newHashMap(universe.length);
3467 for (T constant : universe) {
3468 directory.put(((Enum<?>)constant).name(), constant);
3469 }
3470 enumConstantDirectory = directory;
3471 }
3472 return directory;
3473 }
3474 private transient volatile Map<String, T> enumConstantDirectory;
3475
3476 /**
3477 * Casts an object to the class or interface represented
3478 * by this {@code Class} object.
3479 *
3480 * @param obj the object to be cast
3481 * @return the object after casting, or null if obj is null
3482 *
3483 * @throws ClassCastException if the object is not
3484 * null and is not assignable to the type T.
3485 *
3486 * @since 1.5
3487 */
3488 @SuppressWarnings("unchecked")
3489 @IntrinsicCandidate
3490 public T cast(Object obj) {
3491 if (obj != null && !isInstance(obj))
3492 throw new ClassCastException(cannotCastMsg(obj));
3493 return (T) obj;
3494 }
3495
3496 private String cannotCastMsg(Object obj) {
3497 return "Cannot cast " + obj.getClass().getName() + " to " + getName();
3498 }
3499
3500 /**
3501 * Casts this {@code Class} object to represent a subclass of the class
3502 * represented by the specified class object. Checks that the cast
3503 * is valid, and throws a {@code ClassCastException} if it is not. If
3504 * this method succeeds, it always returns a reference to this {@code Class} object.
3505 *
3506 * <p>This method is useful when a client needs to "narrow" the type of
3507 * a {@code Class} object to pass it to an API that restricts the
3508 * {@code Class} objects that it is willing to accept. A cast would
3509 * generate a compile-time warning, as the correctness of the cast
3510 * could not be checked at runtime (because generic types are implemented
3511 * by erasure).
3512 *
3513 * @param <U> the type to cast this {@code Class} object to
3514 * @param clazz the class of the type to cast this {@code Class} object to
3515 * @return this {@code Class} object, cast to represent a subclass of
3516 * the specified class object.
3517 * @throws ClassCastException if this {@code Class} object does not
3518 * represent a subclass of the specified class (here "subclass" includes
3519 * the class itself).
3520 * @since 1.5
3521 */
3522 @SuppressWarnings("unchecked")
3523 public <U> Class<? extends U> asSubclass(Class<U> clazz) {
3524 if (clazz.isAssignableFrom(this))
3525 return (Class<? extends U>) this;
3526 else
3527 throw new ClassCastException(this.toString());
3528 }
3529
3530 /**
3531 * {@inheritDoc}
3532 * <p>Note that any annotation returned by this method is a
3533 * declaration annotation.
3534 *
3535 * @throws NullPointerException {@inheritDoc}
3536 * @since 1.5
3537 */
3538 @Override
3539 @SuppressWarnings("unchecked")
3540 public <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
3541 Objects.requireNonNull(annotationClass);
3542
3543 return (A) annotationData().annotations.get(annotationClass);
3544 }
3545
3546 /**
3547 * {@inheritDoc}
3548 * @throws NullPointerException {@inheritDoc}
3549 * @since 1.5
3550 */
3551 @Override
3552 public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {
3553 return GenericDeclaration.super.isAnnotationPresent(annotationClass);
3554 }
3555
3556 /**
3557 * {@inheritDoc}
3558 * <p>Note that any annotations returned by this method are
3559 * declaration annotations.
3560 *
3561 * @throws NullPointerException {@inheritDoc}
3562 * @since 1.8
3563 */
3564 @Override
3565 public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationClass) {
3566 Objects.requireNonNull(annotationClass);
3567
3568 AnnotationData annotationData = annotationData();
3569 return AnnotationSupport.getAssociatedAnnotations(annotationData.declaredAnnotations,
3570 this,
3571 annotationClass);
3572 }
3573
3574 /**
3575 * {@inheritDoc}
3576 * <p>Note that any annotations returned by this method are
3577 * declaration annotations.
3578 *
3579 * @since 1.5
3580 */
3581 @Override
3582 public Annotation[] getAnnotations() {
3583 return AnnotationParser.toArray(annotationData().annotations);
3584 }
3585
3586 /**
3587 * {@inheritDoc}
3588 * <p>Note that any annotation returned by this method is a
3589 * declaration annotation.
3590 *
3591 * @throws NullPointerException {@inheritDoc}
3592 * @since 1.8
3593 */
3594 @Override
3595 @SuppressWarnings("unchecked")
3596 public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationClass) {
3597 Objects.requireNonNull(annotationClass);
3598
3599 return (A) annotationData().declaredAnnotations.get(annotationClass);
3600 }
3601
3602 /**
3603 * {@inheritDoc}
3604 * <p>Note that any annotations returned by this method are
3605 * declaration annotations.
3606 *
3607 * @throws NullPointerException {@inheritDoc}
3608 * @since 1.8
3609 */
3610 @Override
3611 public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationClass) {
3612 Objects.requireNonNull(annotationClass);
3613
3614 return AnnotationSupport.getDirectlyAndIndirectlyPresent(annotationData().declaredAnnotations,
3615 annotationClass);
3616 }
3617
3618 /**
3619 * {@inheritDoc}
3620 * <p>Note that any annotations returned by this method are
3621 * declaration annotations.
3622 *
3623 * @since 1.5
3624 */
3625 @Override
3626 public Annotation[] getDeclaredAnnotations() {
3627 return AnnotationParser.toArray(annotationData().declaredAnnotations);
3628 }
3629
3630 // annotation data that might get invalidated when JVM TI RedefineClasses() is called
3631 private static class AnnotationData {
3632 final Map<Class<? extends Annotation>, Annotation> annotations;
3633 final Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
3634
3635 // Value of classRedefinedCount when we created this AnnotationData instance
3636 final int redefinedCount;
3637
3638 AnnotationData(Map<Class<? extends Annotation>, Annotation> annotations,
3639 Map<Class<? extends Annotation>, Annotation> declaredAnnotations,
3640 int redefinedCount) {
3641 this.annotations = annotations;
3642 this.declaredAnnotations = declaredAnnotations;
3643 this.redefinedCount = redefinedCount;
3644 }
3645 }
3646
3647 // Annotations cache
3648 @SuppressWarnings("UnusedDeclaration")
3649 private transient volatile AnnotationData annotationData;
3650
3651 private AnnotationData annotationData() {
3652 while (true) { // retry loop
3653 AnnotationData annotationData = this.annotationData;
3654 int classRedefinedCount = this.classRedefinedCount;
3655 if (annotationData != null &&
3656 annotationData.redefinedCount == classRedefinedCount) {
3657 return annotationData;
3658 }
3659 // null or stale annotationData -> optimistically create new instance
3660 AnnotationData newAnnotationData = createAnnotationData(classRedefinedCount);
3661 // try to install it
3662 if (Atomic.casAnnotationData(this, annotationData, newAnnotationData)) {
3663 // successfully installed new AnnotationData
3664 return newAnnotationData;
3665 }
3666 }
3667 }
3668
3669 private AnnotationData createAnnotationData(int classRedefinedCount) {
3670 Map<Class<? extends Annotation>, Annotation> declaredAnnotations =
3671 AnnotationParser.parseAnnotations(getRawAnnotations(), getConstantPool(), this);
3672 Class<?> superClass = getSuperclass();
3673 Map<Class<? extends Annotation>, Annotation> annotations = null;
3674 if (superClass != null) {
3675 Map<Class<? extends Annotation>, Annotation> superAnnotations =
3676 superClass.annotationData().annotations;
3677 for (Map.Entry<Class<? extends Annotation>, Annotation> e : superAnnotations.entrySet()) {
3678 Class<? extends Annotation> annotationClass = e.getKey();
3679 if (AnnotationType.getInstance(annotationClass).isInherited()) {
3680 if (annotations == null) { // lazy construction
3681 annotations = LinkedHashMap.newLinkedHashMap(Math.max(
3682 declaredAnnotations.size(),
3683 Math.min(12, declaredAnnotations.size() + superAnnotations.size())
3684 )
3685 );
3686 }
3687 annotations.put(annotationClass, e.getValue());
3688 }
3689 }
3690 }
3691 if (annotations == null) {
3692 // no inherited annotations -> share the Map with declaredAnnotations
3693 annotations = declaredAnnotations;
3694 } else {
3695 // at least one inherited annotation -> declared may override inherited
3696 annotations.putAll(declaredAnnotations);
3697 }
3698 return new AnnotationData(annotations, declaredAnnotations, classRedefinedCount);
3699 }
3700
3701 // Annotation interfaces cache their internal (AnnotationType) form
3702
3703 @SuppressWarnings("UnusedDeclaration")
3704 private transient volatile AnnotationType annotationType;
3705
3706 boolean casAnnotationType(AnnotationType oldType, AnnotationType newType) {
3707 return Atomic.casAnnotationType(this, oldType, newType);
3708 }
3709
3710 AnnotationType getAnnotationType() {
3711 return annotationType;
3712 }
3713
3714 Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap() {
3715 return annotationData().declaredAnnotations;
3716 }
3717
3718 /* Backing store of user-defined values pertaining to this class.
3719 * Maintained by the ClassValue class.
3720 */
3721 transient ClassValue.ClassValueMap classValueMap;
3722
3723 /**
3724 * Returns an {@code AnnotatedType} object that represents the use of a
3725 * type to specify the superclass of the entity represented by this {@code
3726 * Class} object. (The <em>use</em> of type Foo to specify the superclass
3727 * in '... extends Foo' is distinct from the <em>declaration</em> of class
3728 * Foo.)
3729 *
3730 * <p> If this {@code Class} object represents a class whose declaration
3731 * does not explicitly indicate an annotated superclass, then the return
3732 * value is an {@code AnnotatedType} object representing an element with no
3733 * annotations.
3734 *
3735 * <p> If this {@code Class} represents either the {@code Object} class, an
3736 * interface type, an array type, a primitive type, or void, the return
3737 * value is {@code null}.
3738 *
3739 * @return an object representing the superclass
3740 * @since 1.8
3741 */
3742 public AnnotatedType getAnnotatedSuperclass() {
3743 if (this == Object.class ||
3744 isInterface() ||
3745 isArray() ||
3746 isPrimitive() ||
3747 this == Void.TYPE) {
3748 return null;
3749 }
3750
3751 return TypeAnnotationParser.buildAnnotatedSuperclass(getRawTypeAnnotations(), getConstantPool(), this);
3752 }
3753
3754 /**
3755 * Returns an array of {@code AnnotatedType} objects that represent the use
3756 * of types to specify superinterfaces of the entity represented by this
3757 * {@code Class} object. (The <em>use</em> of type Foo to specify a
3758 * superinterface in '... implements Foo' is distinct from the
3759 * <em>declaration</em> of interface Foo.)
3760 *
3761 * <p> If this {@code Class} object represents a class, the return value is
3762 * an array containing objects representing the uses of interface types to
3763 * specify interfaces implemented by the class. The order of the objects in
3764 * the array corresponds to the order of the interface types used in the
3765 * 'implements' clause of the declaration of this {@code Class} object.
3766 *
3767 * <p> If this {@code Class} object represents an interface, the return
3768 * value is an array containing objects representing the uses of interface
3769 * types to specify interfaces directly extended by the interface. The
3770 * order of the objects in the array corresponds to the order of the
3771 * interface types used in the 'extends' clause of the declaration of this
3772 * {@code Class} object.
3773 *
3774 * <p> If this {@code Class} object represents a class or interface whose
3775 * declaration does not explicitly indicate any annotated superinterfaces,
3776 * the return value is an array of length 0.
3777 *
3778 * <p> If this {@code Class} object represents either the {@code Object}
3779 * class, an array type, a primitive type, or void, the return value is an
3780 * array of length 0.
3781 *
3782 * @return an array representing the superinterfaces
3783 * @since 1.8
3784 */
3785 public AnnotatedType[] getAnnotatedInterfaces() {
3786 return TypeAnnotationParser.buildAnnotatedInterfaces(getRawTypeAnnotations(), getConstantPool(), this);
3787 }
3788
3789 private native Class<?> getNestHost0();
3790
3791 /**
3792 * Returns the nest host of the <a href=#nest>nest</a> to which the class
3793 * or interface represented by this {@code Class} object belongs.
3794 * Every class and interface belongs to exactly one nest.
3795 *
3796 * If the nest host of this class or interface has previously
3797 * been determined, then this method returns the nest host.
3798 * If the nest host of this class or interface has
3799 * not previously been determined, then this method determines the nest
3800 * host using the algorithm of JVMS 5.4.4, and returns it.
3801 *
3802 * Often, a class or interface belongs to a nest consisting only of itself,
3803 * in which case this method returns {@code this} to indicate that the class
3804 * or interface is the nest host.
3805 *
3806 * <p>If this {@code Class} object represents a primitive type, an array type,
3807 * or {@code void}, then this method returns {@code this},
3808 * indicating that the represented entity belongs to the nest consisting only of
3809 * itself, and is the nest host.
3810 *
3811 * @return the nest host of this class or interface
3812 *
3813 * @since 11
3814 * @jvms 4.7.28 The {@code NestHost} Attribute
3815 * @jvms 4.7.29 The {@code NestMembers} Attribute
3816 * @jvms 5.4.4 Access Control
3817 */
3818 public Class<?> getNestHost() {
3819 if (isPrimitive() || isArray()) {
3820 return this;
3821 }
3822 return getNestHost0();
3823 }
3824
3825 /**
3826 * Determines if the given {@code Class} is a nestmate of the
3827 * class or interface represented by this {@code Class} object.
3828 * Two classes or interfaces are nestmates
3829 * if they have the same {@linkplain #getNestHost() nest host}.
3830 *
3831 * @param c the class to check
3832 * @return {@code true} if this class and {@code c} are members of
3833 * the same nest; and {@code false} otherwise.
3834 *
3835 * @since 11
3836 */
3837 public boolean isNestmateOf(Class<?> c) {
3838 if (this == c) {
3839 return true;
3840 }
3841 if (isPrimitive() || isArray() ||
3842 c.isPrimitive() || c.isArray()) {
3843 return false;
3844 }
3845
3846 return getNestHost() == c.getNestHost();
3847 }
3848
3849 private native Class<?>[] getNestMembers0();
3850
3851 /**
3852 * Returns an array containing {@code Class} objects representing all the
3853 * classes and interfaces that are members of the nest to which the class
3854 * or interface represented by this {@code Class} object belongs.
3855 *
3856 * First, this method obtains the {@linkplain #getNestHost() nest host},
3857 * {@code H}, of the nest to which the class or interface represented by
3858 * this {@code Class} object belongs. The zeroth element of the returned
3859 * array is {@code H}.
3860 *
3861 * Then, for each class or interface {@code C} which is recorded by {@code H}
3862 * as being a member of its nest, this method attempts to obtain the {@code Class}
3863 * object for {@code C} (using {@linkplain #getClassLoader() the defining class
3864 * loader} of the current {@code Class} object), and then obtains the
3865 * {@linkplain #getNestHost() nest host} of the nest to which {@code C} belongs.
3866 * The classes and interfaces which are recorded by {@code H} as being members
3867 * of its nest, and for which {@code H} can be determined as their nest host,
3868 * are indicated by subsequent elements of the returned array. The order of
3869 * such elements is unspecified. Duplicates are permitted.
3870 *
3871 * <p>If this {@code Class} object represents a primitive type, an array type,
3872 * or {@code void}, then this method returns a single-element array containing
3873 * {@code this}.
3874 *
3875 * @apiNote
3876 * The returned array includes only the nest members recorded in the {@code NestMembers}
3877 * attribute, and not any hidden classes that were added to the nest via
3878 * {@link MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
3879 * Lookup::defineHiddenClass}.
3880 *
3881 * @return an array of all classes and interfaces in the same nest as
3882 * this class or interface
3883 *
3884 * @since 11
3885 * @see #getNestHost()
3886 * @jvms 4.7.28 The {@code NestHost} Attribute
3887 * @jvms 4.7.29 The {@code NestMembers} Attribute
3888 */
3889 public Class<?>[] getNestMembers() {
3890 if (isPrimitive() || isArray()) {
3891 return new Class<?>[] { this };
3892 }
3893 Class<?>[] members = getNestMembers0();
3894 // Can't actually enable this due to bootstrapping issues
3895 // assert(members.length != 1 || members[0] == this); // expected invariant from VM
3896 return members;
3897 }
3898
3899 /**
3900 * Returns the descriptor string of the entity (class, interface, array class,
3901 * primitive type, or {@code void}) represented by this {@code Class} object.
3902 *
3903 * <p> If this {@code Class} object represents a class or interface,
3904 * not an array class, then:
3905 * <ul>
3906 * <li> If the class or interface is not {@linkplain Class#isHidden() hidden},
3907 * then the result is a field descriptor (JVMS {@jvms 4.3.2})
3908 * for the class or interface. Calling
3909 * {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}
3910 * with the result descriptor string produces a {@link ClassDesc ClassDesc}
3911 * describing this class or interface.
3912 * <li> If the class or interface is {@linkplain Class#isHidden() hidden},
3913 * then the result is a string of the form:
3914 * <blockquote>
3915 * {@code "L" +} <em>N</em> {@code + "." + <suffix> + ";"}
3916 * </blockquote>
3917 * where <em>N</em> is the {@linkplain ClassLoader##binary-name binary name}
3918 * encoded in internal form indicated by the {@code class} file passed to
3919 * {@link MethodHandles.Lookup#defineHiddenClass(byte[], boolean, MethodHandles.Lookup.ClassOption...)
3920 * Lookup::defineHiddenClass}, and {@code <suffix>} is an unqualified name.
3921 * A hidden class or interface has no {@linkplain ClassDesc nominal descriptor}.
3922 * The result string is not a type descriptor.
3923 * </ul>
3924 *
3925 * <p> If this {@code Class} object represents an array class, then
3926 * the result is a string consisting of one or more '{@code [}' characters
3927 * representing the depth of the array nesting, followed by the
3928 * descriptor string of the element type.
3929 * <ul>
3930 * <li> If the element type is not a {@linkplain Class#isHidden() hidden} class
3931 * or interface, then this array class can be described nominally.
3932 * Calling {@link ClassDesc#ofDescriptor(String) ClassDesc::ofDescriptor}
3933 * with the result descriptor string produces a {@link ClassDesc ClassDesc}
3934 * describing this array class.
3935 * <li> If the element type is a {@linkplain Class#isHidden() hidden} class or
3936 * interface, then this array class cannot be described nominally.
3937 * The result string is not a type descriptor.
3938 * </ul>
3939 *
3940 * <p> If this {@code Class} object represents a primitive type or
3941 * {@code void}, then the result is a field descriptor string which
3942 * is a one-letter code corresponding to a primitive type or {@code void}
3943 * ({@code "B", "C", "D", "F", "I", "J", "S", "Z", "V"}) (JVMS {@jvms 4.3.2}).
3944 *
3945 * @return the descriptor string for this {@code Class} object
3946 * @jvms 4.3.2 Field Descriptors
3947 * @since 12
3948 */
3949 @Override
3950 public String descriptorString() {
3951 if (isPrimitive())
3952 return Wrapper.forPrimitiveType(this).basicTypeString();
3953
3954 if (isArray()) {
3955 return "[".concat(componentType.descriptorString());
3956 } else if (isHidden()) {
3957 String name = getName();
3958 int index = name.indexOf('/');
3959 return new StringBuilder(name.length() + 2)
3960 .append('L')
3961 .append(name.substring(0, index).replace('.', '/'))
3962 .append('.')
3963 .append(name, index + 1, name.length())
3964 .append(';')
3965 .toString();
3966 } else {
3967 String name = getName().replace('.', '/');
3968 return StringConcatHelper.concat("L", name, ";");
3969 }
3970 }
3971
3972 /**
3973 * Returns the component type of this {@code Class}, if it describes
3974 * an array type, or {@code null} otherwise.
3975 *
3976 * @implSpec
3977 * Equivalent to {@link Class#getComponentType()}.
3978 *
3979 * @return a {@code Class} describing the component type, or {@code null}
3980 * if this {@code Class} does not describe an array type
3981 * @since 12
3982 */
3983 @Override
3984 public Class<?> componentType() {
3985 return isArray() ? componentType : null;
3986 }
3987
3988 /**
3989 * Returns a {@code Class} for an array type whose component type
3990 * is described by this {@linkplain Class}.
3991 *
3992 * @throws UnsupportedOperationException if this component type is {@linkplain
3993 * Void#TYPE void} or if the number of dimensions of the resulting array
3994 * type would exceed 255.
3995 * @return a {@code Class} describing the array type
3996 * @jvms 4.3.2 Field Descriptors
3997 * @jvms 4.4.1 The {@code CONSTANT_Class_info} Structure
3998 * @since 12
3999 */
4000 @Override
4001 public Class<?> arrayType() {
4002 try {
4003 return Array.newInstance(this, 0).getClass();
4004 } catch (IllegalArgumentException iae) {
4005 throw new UnsupportedOperationException(iae);
4006 }
4007 }
4008
4009 /**
4010 * Returns a nominal descriptor for this instance, if one can be
4011 * constructed, or an empty {@link Optional} if one cannot be.
4012 *
4013 * @return An {@link Optional} containing the resulting nominal descriptor,
4014 * or an empty {@link Optional} if one cannot be constructed.
4015 * @since 12
4016 */
4017 @Override
4018 public Optional<ClassDesc> describeConstable() {
4019 Class<?> c = isArray() ? elementType() : this;
4020 return c.isHidden() ? Optional.empty()
4021 : Optional.of(ConstantUtils.classDesc(this));
4022 }
4023
4024 /**
4025 * Returns {@code true} if and only if the underlying class is a hidden class.
4026 *
4027 * @return {@code true} if and only if this class is a hidden class.
4028 *
4029 * @since 15
4030 * @see MethodHandles.Lookup#defineHiddenClass
4031 * @see Class##hiddenClasses Hidden Classes
4032 */
4033 @IntrinsicCandidate
4034 public native boolean isHidden();
4035
4036 /**
4037 * Returns an array containing {@code Class} objects representing the
4038 * direct subinterfaces or subclasses permitted to extend or
4039 * implement this class or interface if it is sealed. The order of such elements
4040 * is unspecified. The array is empty if this sealed class or interface has no
4041 * permitted subclass. If this {@code Class} object represents a primitive type,
4042 * {@code void}, an array type, or a class or interface that is not sealed,
4043 * that is {@link #isSealed()} returns {@code false}, then this method returns {@code null}.
4044 * Conversely, if {@link #isSealed()} returns {@code true}, then this method
4045 * returns a non-null value.
4046 *
4047 * For each class or interface {@code C} which is recorded as a permitted
4048 * direct subinterface or subclass of this class or interface,
4049 * this method attempts to obtain the {@code Class}
4050 * object for {@code C} (using {@linkplain #getClassLoader() the defining class
4051 * loader} of the current {@code Class} object).
4052 * The {@code Class} objects which can be obtained and which are direct
4053 * subinterfaces or subclasses of this class or interface,
4054 * are indicated by elements of the returned array. If a {@code Class} object
4055 * cannot be obtained, it is silently ignored, and not included in the result
4056 * array.
4057 *
4058 * @return an array of {@code Class} objects of the permitted subclasses of this class
4059 * or interface, or {@code null} if this class or interface is not sealed.
4060 *
4061 * @jls 8.1 Class Declarations
4062 * @jls 9.1 Interface Declarations
4063 * @since 17
4064 */
4065 public Class<?>[] getPermittedSubclasses() {
4066 Class<?>[] subClasses;
4067 if (isArray() || isPrimitive() || (subClasses = getPermittedSubclasses0()) == null) {
4068 return null;
4069 }
4070 if (subClasses.length > 0) {
4071 if (Arrays.stream(subClasses).anyMatch(c -> !isDirectSubType(c))) {
4072 subClasses = Arrays.stream(subClasses)
4073 .filter(this::isDirectSubType)
4074 .toArray(s -> new Class<?>[s]);
4075 }
4076 }
4077 return subClasses;
4078 }
4079
4080 private boolean isDirectSubType(Class<?> c) {
4081 if (isInterface()) {
4082 for (Class<?> i : c.getInterfaces(/* cloneArray */ false)) {
4083 if (i == this) {
4084 return true;
4085 }
4086 }
4087 } else {
4088 return c.getSuperclass() == this;
4089 }
4090 return false;
4091 }
4092
4093 /**
4094 * Returns {@code true} if and only if this {@code Class} object represents
4095 * a sealed class or interface. If this {@code Class} object represents a
4096 * primitive type, {@code void}, or an array type, this method returns
4097 * {@code false}. A sealed class or interface has (possibly zero) permitted
4098 * subclasses; {@link #getPermittedSubclasses()} returns a non-null but
4099 * possibly empty value for a sealed class or interface.
4100 *
4101 * @return {@code true} if and only if this {@code Class} object represents
4102 * a sealed class or interface.
4103 *
4104 * @jls 8.1 Class Declarations
4105 * @jls 9.1 Interface Declarations
4106 * @since 17
4107 */
4108 public boolean isSealed() {
4109 if (isArray() || isPrimitive()) {
4110 return false;
4111 }
4112 return getPermittedSubclasses() != null;
4113 }
4114
4115 private native Class<?>[] getPermittedSubclasses0();
4116
4117 /*
4118 * Return the class's major and minor class file version packed into an int.
4119 * The high order 16 bits contain the class's minor version. The low order
4120 * 16 bits contain the class's major version.
4121 *
4122 * If the class is an array type then the class file version of its element
4123 * type is returned. If the class is a primitive type then the latest class
4124 * file major version is returned and zero is returned for the minor version.
4125 */
4126 int getClassFileVersion() {
4127 Class<?> c = isArray() ? elementType() : this;
4128 return c.getClassFileVersion0();
4129 }
4130
4131 private native int getClassFileVersion0();
4132
4133 /*
4134 * Return the access flags as they were in the class's bytecode, including
4135 * the original setting of ACC_SUPER.
4136 *
4137 * If the class is an array type then the access flags of the element type is
4138 * returned. If the class is a primitive then ACC_ABSTRACT | ACC_FINAL | ACC_PUBLIC.
4139 */
4140 private int getClassAccessFlagsRaw() {
4141 Class<?> c = isArray() ? elementType() : this;
4142 return c.getClassAccessFlagsRaw0();
4143 }
4144
4145 private native int getClassAccessFlagsRaw0();
4146 }