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