1 /*
2 * Copyright (c) 1999, 2023, 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.reflect;
27
28 import java.lang.invoke.MethodHandle;
29 import java.lang.invoke.MethodHandles;
30 import java.lang.invoke.MethodType;
31 import java.lang.invoke.WrongMethodTypeException;
32 import java.lang.module.ModuleDescriptor;
33 import java.security.AccessController;
34 import java.security.PrivilegedAction;
35 import java.util.ArrayDeque;
36 import java.util.Arrays;
37 import java.util.Collections;
38 import java.util.Deque;
39 import java.util.HashMap;
40 import java.util.HashSet;
41 import java.util.IdentityHashMap;
42 import java.util.List;
43 import java.util.Map;
44 import java.util.Objects;
45 import java.util.Set;
46 import java.util.concurrent.ConcurrentHashMap;
47 import java.util.concurrent.atomic.AtomicInteger;
48 import java.util.concurrent.atomic.AtomicLong;
49 import java.util.function.BooleanSupplier;
50
51 import jdk.internal.access.JavaLangAccess;
52 import jdk.internal.access.SharedSecrets;
53 import jdk.internal.value.PrimitiveClass;
54 import jdk.internal.module.Modules;
55 import jdk.internal.misc.VM;
56 import jdk.internal.reflect.CallerSensitive;
57 import jdk.internal.reflect.Reflection;
58 import jdk.internal.loader.ClassLoaderValue;
59 import jdk.internal.vm.annotation.Stable;
60 import sun.reflect.misc.ReflectUtil;
61 import sun.security.action.GetPropertyAction;
62 import sun.security.util.SecurityConstants;
63
64 import static java.lang.invoke.MethodType.methodType;
65 import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC;
66
67 /**
68 *
69 * {@code Proxy} provides static methods for creating objects that act like instances
70 * of interfaces but allow for customized method invocation.
71 * To create a proxy instance for some interface {@code Foo}:
72 * <pre>{@code
73 * InvocationHandler handler = new MyInvocationHandler(...);
74 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
75 * new Class<?>[] { Foo.class },
76 * handler);
77 * }</pre>
78 *
79 * <p>
80 * A <em>proxy class</em> is a class created at runtime that implements a specified
81 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em>
82 * is an instance of a proxy class.
83 *
84 * Each proxy instance has an associated <i>invocation handler</i>
85 * object, which implements the interface {@link InvocationHandler}.
86 * A method invocation on a proxy instance through one of its proxy
87 * interfaces will be dispatched to the {@link InvocationHandler#invoke
88 * invoke} method of the instance's invocation handler, passing the proxy
89 * instance, a {@code java.lang.reflect.Method} object identifying
90 * the method that was invoked, and an array of type {@code Object}
91 * containing the arguments. The invocation handler processes the
92 * encoded method invocation as appropriate and the result that it
93 * returns will be returned as the result of the method invocation on
94 * the proxy instance.
95 *
96 * <p>A proxy class has the following properties:
97 *
98 * <ul>
99 * <li>The unqualified name of a proxy class is unspecified. The space
100 * of class names that begin with the string {@code "$Proxy"}
101 * should be, however, reserved for proxy classes.
102 *
103 * <li>The package and module in which a proxy class is defined is specified
104 * <a href="#membership">below</a>.
105 *
106 * <li>A proxy class is <em>final and non-abstract</em>.
107 *
108 * <li>A proxy class extends {@code java.lang.reflect.Proxy}.
109 *
110 * <li>A proxy class implements exactly the interfaces specified at its
111 * creation, in the same order. Invoking {@link Class#getInterfaces() getInterfaces}
112 * on its {@code Class} object will return an array containing the same
113 * list of interfaces (in the order specified at its creation), invoking
114 * {@link Class#getMethods getMethods} on its {@code Class} object will return
115 * an array of {@code Method} objects that include all of the
116 * methods in those interfaces, and invoking {@code getMethod} will
117 * find methods in the proxy interfaces as would be expected.
118 *
119 * <li>The {@link java.security.ProtectionDomain} of a proxy class
120 * is the same as that of system classes loaded by the bootstrap class
121 * loader, such as {@code java.lang.Object}, because the code for a
122 * proxy class is generated by trusted system code. This protection
123 * domain will typically be granted {@code java.security.AllPermission}.
124 *
125 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used
126 * to determine if a given class is a proxy class.
127 * </ul>
128 *
129 * <p>A proxy instance has the following properties:
130 *
131 * <ul>
132 * <li>Given a proxy instance {@code proxy} and one of the
133 * interfaces, {@code Foo}, implemented by its proxy class, the
134 * following expression will return true:
135 * <pre>
136 * {@code proxy instanceof Foo}
137 * </pre>
138 * and the following cast operation will succeed (rather than throwing
139 * a {@code ClassCastException}):
140 * <pre>
141 * {@code (Foo) proxy}
142 * </pre>
143 *
144 * <li>Each proxy instance has an associated invocation handler, the one
145 * that was passed to its constructor. The static
146 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method
147 * will return the invocation handler associated with the proxy instance
148 * passed as its argument.
149 *
150 * <li>An interface method invocation on a proxy instance will be
151 * encoded and dispatched to the invocation handler's {@link
152 * InvocationHandler#invoke invoke} method as described in the
153 * documentation for that method.
154 *
155 * <li>A proxy interface may define a default method or inherit
156 * a default method from its superinterface directly or indirectly.
157 * An invocation handler can invoke a default method of a proxy interface
158 * by calling {@link InvocationHandler#invokeDefault(Object, Method, Object...)
159 * InvocationHandler::invokeDefault}.
160 *
161 * <li>An invocation of the {@code hashCode},
162 * {@code equals}, or {@code toString} methods declared in
163 * {@code java.lang.Object} on a proxy instance will be encoded and
164 * dispatched to the invocation handler's {@code invoke} method in
165 * the same manner as interface method invocations are encoded and
166 * dispatched, as described above. The declaring class of the
167 * {@code Method} object passed to {@code invoke} will be
168 * {@code java.lang.Object}. Other public methods of a proxy
169 * instance inherited from {@code java.lang.Object} are not
170 * overridden by a proxy class, so invocations of those methods behave
171 * like they do for instances of {@code java.lang.Object}.
172 * </ul>
173 *
174 * <h2><a id="membership">Package and Module Membership of Proxy Class</a></h2>
175 *
176 * The package and module to which a proxy class belongs are chosen such that
177 * the accessibility of the proxy class is in line with the accessibility of
178 * the proxy interfaces. Specifically, the package and the module membership
179 * of a proxy class defined via the
180 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or
181 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)}
182 * methods is specified as follows:
183 *
184 * <ol>
185 * <li>If all the proxy interfaces are in <em>exported</em> or <em>open</em>
186 * packages:
187 * <ol type="a">
188 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
189 * <em>public</em> in an unconditionally exported but non-open package.
190 * The name of the package and the module are unspecified.</li>
191 *
192 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
193 * the proxy class is <em>non-public</em> in the package and module of the
194 * non-public interfaces. All the non-public interfaces must be in the same
195 * package and module; otherwise, proxying them is
196 * <a href="#restrictions">not possible</a>.</li>
197 * </ol>
198 * </li>
199 * <li>If at least one proxy interface is in a package that is
200 * <em>non-exported</em> and <em>non-open</em>:
201 * <ol type="a">
202 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
203 * <em>public</em> in a <em>non-exported</em>, <em>non-open</em> package of
204 * <a href="#dynamicmodule"><em>dynamic module</em>.</a>
205 * The names of the package and the module are unspecified.</li>
206 *
207 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
208 * the proxy class is <em>non-public</em> in the package and module of the
209 * non-public interfaces. All the non-public interfaces must be in the same
210 * package and module; otherwise, proxying them is
211 * <a href="#restrictions">not possible</a>.</li>
212 * </ol>
213 * </li>
214 * </ol>
215 *
216 * <p>
217 * Note that if proxy interfaces with a mix of accessibilities -- for example,
218 * an exported public interface and a non-exported non-public interface -- are
219 * proxied by the same instance, then the proxy class's accessibility is
220 * governed by the least accessible proxy interface.
221 * <p>
222 * Note that it is possible for arbitrary code to obtain access to a proxy class
223 * in an open package with {@link AccessibleObject#setAccessible setAccessible},
224 * whereas a proxy class in a non-open package is never accessible to
225 * code outside the module of the proxy class.
226 *
227 * <p>
228 * Throughout this specification, a "non-exported package" refers to a package
229 * that is not exported to all modules, and a "non-open package" refers to
230 * a package that is not open to all modules. Specifically, these terms refer to
231 * a package that either is not exported/open by its containing module or is
232 * exported/open in a qualified fashion by its containing module.
233 *
234 * <h3><a id="dynamicmodule">Dynamic Modules</a></h3>
235 * <p>
236 * A dynamic module is a named module generated at runtime. A proxy class
237 * defined in a dynamic module is encapsulated and not accessible to any module.
238 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in
239 * a dynamic module will throw {@code IllegalAccessException};
240 * {@code Proxy.newProxyInstance} method should be used instead.
241 *
242 * <p>
243 * A dynamic module can read the modules of all of the superinterfaces of a proxy
244 * class and the modules of the classes and interfaces referenced by
245 * all public method signatures of a proxy class. If a superinterface or
246 * a referenced class or interface, say {@code T}, is in a non-exported package,
247 * the {@linkplain Module module} of {@code T} is updated to export the
248 * package of {@code T} to the dynamic module.
249 *
250 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3>
251 *
252 * <p>When two or more proxy interfaces contain a method with
253 * the same name and parameter signature, the order of the proxy class's
254 * interfaces becomes significant. When such a <i>duplicate method</i>
255 * is invoked on a proxy instance, the {@code Method} object passed
256 * to the invocation handler will not necessarily be the one whose
257 * declaring class is assignable from the reference type of the interface
258 * that the proxy's method was invoked through. This limitation exists
259 * because the corresponding method implementation in the generated proxy
260 * class cannot determine which interface it was invoked through.
261 * Therefore, when a duplicate method is invoked on a proxy instance,
262 * the {@code Method} object for the method in the foremost interface
263 * that contains the method (either directly or inherited through a
264 * superinterface) in the proxy class's list of interfaces is passed to
265 * the invocation handler's {@code invoke} method, regardless of the
266 * reference type through which the method invocation occurred.
267 *
268 * <p>If a proxy interface contains a method with the same name and
269 * parameter signature as the {@code hashCode}, {@code equals},
270 * or {@code toString} methods of {@code java.lang.Object},
271 * when such a method is invoked on a proxy instance, the
272 * {@code Method} object passed to the invocation handler will have
273 * {@code java.lang.Object} as its declaring class. In other words,
274 * the public, non-final methods of {@code java.lang.Object}
275 * logically precede all of the proxy interfaces for the determination of
276 * which {@code Method} object to pass to the invocation handler.
277 *
278 * <p>Note also that when a duplicate method is dispatched to an
279 * invocation handler, the {@code invoke} method may only throw
280 * checked exception types that are assignable to one of the exception
281 * types in the {@code throws} clause of the method in <i>all</i> of
282 * the proxy interfaces that it can be invoked through. If the
283 * {@code invoke} method throws a checked exception that is not
284 * assignable to any of the exception types declared by the method in one
285 * of the proxy interfaces that it can be invoked through, then an
286 * unchecked {@code UndeclaredThrowableException} will be thrown by
287 * the invocation on the proxy instance. This restriction means that not
288 * all of the exception types returned by invoking
289 * {@code getExceptionTypes} on the {@code Method} object
290 * passed to the {@code invoke} method can necessarily be thrown
291 * successfully by the {@code invoke} method.
292 *
293 * @author Peter Jones
294 * @see InvocationHandler
295 * @since 1.3
296 * @revised 9
297 */
298 public class Proxy implements java.io.Serializable {
299 @java.io.Serial
300 private static final long serialVersionUID = -2222568056686623797L;
301
302 /** parameter types of a proxy class constructor */
303 private static final Class<?>[] constructorParams =
304 { InvocationHandler.class };
305
306 /**
307 * a cache of proxy constructors with
308 * {@link Constructor#setAccessible(boolean) accessible} flag already set
309 */
310 private static final ClassLoaderValue<Constructor<?>> proxyCache =
311 new ClassLoaderValue<>();
312
313 /**
314 * the invocation handler for this proxy instance.
315 * @serial
316 */
317 @SuppressWarnings("serial") // Not statically typed as Serializable
318 protected InvocationHandler h;
319
320 /**
321 * Prohibits instantiation.
322 */
323 private Proxy() {
324 }
325
326 /**
327 * Constructs a new {@code Proxy} instance from a subclass
328 * (typically, a dynamic proxy class) with the specified value
329 * for its invocation handler.
330 *
331 * @param h the invocation handler for this proxy instance
332 *
333 * @throws NullPointerException if the given invocation handler, {@code h},
334 * is {@code null}.
335 */
336 protected Proxy(InvocationHandler h) {
337 Objects.requireNonNull(h);
338 this.h = h;
339 }
340
341 /**
342 * Returns the {@code java.lang.Class} object for a proxy class
343 * given a class loader and an array of interfaces. The proxy class
344 * will be defined by the specified class loader and will implement
345 * all of the supplied interfaces. If any of the given interfaces
346 * is non-public, the proxy class will be non-public. If a proxy class
347 * for the same permutation of interfaces has already been defined by the
348 * class loader, then the existing proxy class will be returned; otherwise,
349 * a proxy class for those interfaces will be generated dynamically
350 * and defined by the class loader.
351 *
352 * @param loader the class loader to define the proxy class
353 * @param interfaces the list of interfaces for the proxy class
354 * to implement
355 * @return a proxy class that is defined in the specified class loader
356 * and that implements the specified interfaces
357 * @throws IllegalArgumentException if any of the <a href="#restrictions">
358 * restrictions</a> on the parameters are violated
359 * @throws SecurityException if a security manager, <em>s</em>, is present
360 * and any of the following conditions is met:
361 * <ul>
362 * <li> the given {@code loader} is {@code null} and
363 * the caller's class loader is not {@code null} and the
364 * invocation of {@link SecurityManager#checkPermission
365 * s.checkPermission} with
366 * {@code RuntimePermission("getClassLoader")} permission
367 * denies access.</li>
368 * <li> for each proxy interface, {@code intf},
369 * the caller's class loader is not the same as or an
370 * ancestor of the class loader for {@code intf} and
371 * invocation of {@link SecurityManager#checkPackageAccess
372 * s.checkPackageAccess()} denies access to {@code intf}.</li>
373 * </ul>
374 * @throws NullPointerException if the {@code interfaces} array
375 * argument or any of its elements are {@code null}
376 *
377 * @deprecated Proxy classes generated in a named module are encapsulated
378 * and not accessible to code outside its module.
379 * {@link Constructor#newInstance(Object...) Constructor.newInstance}
380 * will throw {@code IllegalAccessException} when it is called on
381 * an inaccessible proxy class.
382 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
383 * to create a proxy instance instead.
384 *
385 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
386 * @revised 9
387 */
388 @Deprecated
389 @CallerSensitive
390 public static Class<?> getProxyClass(ClassLoader loader,
391 Class<?>... interfaces)
392 throws IllegalArgumentException
393 {
394 @SuppressWarnings("removal")
395 Class<?> caller = System.getSecurityManager() == null
396 ? null
397 : Reflection.getCallerClass();
398
399 return getProxyConstructor(caller, loader, interfaces)
400 .getDeclaringClass();
401 }
402
403 /**
404 * Returns the {@code Constructor} object of a proxy class that takes a
405 * single argument of type {@link InvocationHandler}, given a class loader
406 * and an array of interfaces. The returned constructor will have the
407 * {@link Constructor#setAccessible(boolean) accessible} flag already set.
408 *
409 * @param caller passed from a public-facing @CallerSensitive method if
410 * SecurityManager is set or {@code null} if there's no
411 * SecurityManager
412 * @param loader the class loader to define the proxy class
413 * @param interfaces the list of interfaces for the proxy class
414 * to implement
415 * @return a Constructor of the proxy class taking single
416 * {@code InvocationHandler} parameter
417 */
418 private static Constructor<?> getProxyConstructor(Class<?> caller,
419 ClassLoader loader,
420 Class<?>... interfaces)
421 {
422 // optimization for single interface
423 if (interfaces.length == 1) {
424 Class<?> intf = interfaces[0];
425 if (caller != null) {
426 checkProxyAccess(caller, loader, intf);
427 }
428 return proxyCache.sub(intf).computeIfAbsent(
429 loader,
430 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
431 );
432 } else {
433 // interfaces cloned
434 final Class<?>[] intfsArray = interfaces.clone();
435 if (caller != null) {
436 checkProxyAccess(caller, loader, intfsArray);
437 }
438 final List<Class<?>> intfs = Arrays.asList(intfsArray);
439 return proxyCache.sub(intfs).computeIfAbsent(
440 loader,
441 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
442 );
443 }
444 }
445
446 /*
447 * Check permissions required to create a Proxy class.
448 *
449 * To define a proxy class, it performs the access checks as in
450 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
451 * 1. "getClassLoader" permission check if loader == null
452 * 2. checkPackageAccess on the interfaces it implements
453 *
454 * To get a constructor and new instance of a proxy class, it performs
455 * the package access check on the interfaces it implements
456 * as in Class.getConstructor.
457 *
458 * If an interface is non-public, the proxy class must be defined by
459 * the defining loader of the interface. If the caller's class loader
460 * is not the same as the defining loader of the interface, the VM
461 * will throw IllegalAccessError when the generated proxy class is
462 * being defined.
463 */
464 private static void checkProxyAccess(Class<?> caller,
465 ClassLoader loader,
466 Class<?> ... interfaces)
467 {
468 @SuppressWarnings("removal")
469 SecurityManager sm = System.getSecurityManager();
470 if (sm != null) {
471 ClassLoader ccl = caller.getClassLoader();
472 if (loader == null && ccl != null) {
473 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
474 }
475 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
476 }
477 }
478
479 /**
480 * Builder for a proxy class.
481 *
482 * If the module is not specified in this ProxyBuilder constructor,
483 * it will map from the given loader and interfaces to the module
484 * in which the proxy class will be defined.
485 */
486 private static final class ProxyBuilder {
487 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
488
489 // prefix for all proxy class names
490 private static final String proxyClassNamePrefix = "$Proxy";
491
492 // next number to use for generation of unique proxy class names
493 private static final AtomicLong nextUniqueNumber = new AtomicLong();
494
495 // a reverse cache of defined proxy classes
496 private static final ClassLoaderValue<Boolean> reverseProxyCache =
497 new ClassLoaderValue<>();
498
499 private record ProxyClassContext(Module module, String packageName, int accessFlags) {
500 private ProxyClassContext {
501 if (module.isNamed()) {
502 if (packageName.isEmpty()) {
503 // Per JLS 7.4.2, unnamed package can only exist in unnamed modules.
504 // This means a package-private superinterface exist in the unnamed
505 // package of a named module.
506 throw new InternalError("Unnamed package cannot be added to " + module);
507 }
508
509 if (!module.getDescriptor().packages().contains(packageName)) {
510 throw new InternalError(packageName + " not exist in " + module.getName());
511 }
512
513 if (!module.isOpen(packageName, Proxy.class.getModule())) {
514 // Required for default method invocation
515 throw new InternalError(packageName + " not open to " + Proxy.class.getModule());
516 }
517 } else {
518 if (Modifier.isPublic(accessFlags)) {
519 // All proxy superinterfaces are public, must be in named dynamic module
520 throw new InternalError("public proxy in unnamed module: " + module);
521 }
522 }
523
524 if ((accessFlags & ~(Modifier.PUBLIC | Modifier.IDENTITY)) != 0) {
525 throw new InternalError("proxy access flags must be Modifier.PUBLIC or 0");
526 }
527 }
528 }
529
530 private static Class<?> defineProxyClass(ProxyClassContext context, List<Class<?>> interfaces) {
531 /*
532 * Choose a name for the proxy class to generate.
533 */
534 long num = nextUniqueNumber.getAndIncrement();
535 String proxyName = context.packageName().isEmpty()
536 ? proxyClassNamePrefix + num
537 : context.packageName() + "." + proxyClassNamePrefix + num;
538
539 ClassLoader loader = getLoader(context.module());
540 trace(proxyName, context.module(), loader, interfaces);
541
542 /*
543 * Generate the specified proxy class.
544 */
545 byte[] proxyClassFile = ProxyGenerator.generateProxyClass(loader, proxyName, interfaces,
546 context.accessFlags() | Modifier.FINAL | Modifier.IDENTITY);
547 try {
548 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
549 null, "__dynamic_proxy__");
550 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
551 return pc;
552 } catch (ClassFormatError e) {
553 /*
554 * A ClassFormatError here means that (barring bugs in the
555 * proxy class generation code) there was some other
556 * invalid aspect of the arguments supplied to the proxy
557 * class creation (such as virtual machine limitations
558 * exceeded).
559 */
560 throw new IllegalArgumentException(e.toString());
561 }
562 }
563
564 /**
565 * Test if given class is a class defined by
566 * {@link #defineProxyClass(ProxyClassContext, List)}
567 */
568 static boolean isProxyClass(Class<?> c) {
569 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()),
570 Boolean.TRUE);
571 }
572
573 private static boolean isExportedType(Class<?> c) {
574 String pn = c.getPackageName();
575 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
576 }
577
578 private static boolean isPackagePrivateType(Class<?> c) {
579 return !Modifier.isPublic(c.getModifiers());
580 }
581
582 private static String toDetails(Class<?> c) {
583 String access = "unknown";
584 if (isExportedType(c)) {
585 access = "exported";
586 } else if (isPackagePrivateType(c)) {
587 access = "package-private";
588 } else {
589 access = "module-private";
590 }
591 ClassLoader ld = c.getClassLoader();
592 return String.format(" %s/%s %s loader %s",
593 c.getModule().getName(), c.getName(), access, ld);
594 }
595
596 static void trace(String cn,
597 Module module,
598 ClassLoader loader,
599 List<Class<?>> interfaces) {
600 if (isDebug()) {
601 System.err.format("PROXY: %s/%s defined by %s%n",
602 module.getName(), cn, loader);
603 }
604 if (isDebug("debug")) {
605 interfaces.forEach(c -> System.out.println(toDetails(c)));
606 }
607 }
608
609 private static final String DEBUG =
610 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", "");
611
612 private static boolean isDebug() {
613 return !DEBUG.isEmpty();
614 }
615 private static boolean isDebug(String flag) {
616 return DEBUG.equals(flag);
617 }
618
619 // ProxyBuilder instance members start here....
620
621 private final List<Class<?>> interfaces;
622 private final ProxyClassContext context;
623 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
624 if (!VM.isModuleSystemInited()) {
625 throw new InternalError("Proxy is not supported until "
626 + "module system is fully initialized");
627 }
628 if (interfaces.size() > 65535) {
629 throw new IllegalArgumentException("interface limit exceeded: "
630 + interfaces.size());
631 }
632
633 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
634
635 // IAE if violates any restrictions specified in newProxyInstance
636 validateProxyInterfaces(loader, interfaces, refTypes);
637
638 this.interfaces = interfaces;
639 this.context = proxyClassContext(loader, interfaces, refTypes);
640 assert getLoader(context.module()) == loader;
641 }
642
643 ProxyBuilder(ClassLoader loader, Class<?> intf) {
644 this(loader, Collections.singletonList(intf));
645 }
646
647 /**
648 * Generate a proxy class and return its proxy Constructor with
649 * accessible flag already set. If the target module does not have access
650 * to any interface types, IllegalAccessError will be thrown by the VM
651 * at defineClass time.
652 *
653 * Must call the checkProxyAccess method to perform permission checks
654 * before calling this.
655 */
656 @SuppressWarnings("removal")
657 Constructor<?> build() {
658 Class<?> proxyClass = defineProxyClass(context, interfaces);
659
660 final Constructor<?> cons;
661 try {
662 cons = proxyClass.getConstructor(constructorParams);
663 } catch (NoSuchMethodException e) {
664 throw new InternalError(e.toString(), e);
665 }
666 AccessController.doPrivileged(new PrivilegedAction<Void>() {
667 public Void run() {
668 cons.setAccessible(true);
669 return null;
670 }
671 });
672 return cons;
673 }
674
675 /**
676 * Validate the given proxy interfaces and the given referenced types
677 * are visible to the defining loader.
678 *
679 * @throws IllegalArgumentException if it violates the restrictions
680 * specified in {@link Proxy#newProxyInstance}
681 */
682 private static void validateProxyInterfaces(ClassLoader loader,
683 List<Class<?>> interfaces,
684 Set<Class<?>> refTypes)
685 {
686 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
687 for (Class<?> intf : interfaces) {
688 /*
689 * Verify that the Class object actually represents an
690 * interface.
691 */
692 if (!intf.isInterface()) {
693 throw new IllegalArgumentException(intf.getName() + " is not an interface");
694 }
695
696 if (intf.isHidden()) {
697 throw new IllegalArgumentException(intf.getName() + " is a hidden interface");
698 }
699
700 if (intf.isSealed()) {
701 throw new IllegalArgumentException(intf.getName() + " is a sealed interface");
702 }
703
704 /*
705 * Verify that the class loader resolves the name of this
706 * interface to the same Class object.
707 */
708 ensureVisible(loader, intf);
709
710 /*
711 * Verify that this interface is not a duplicate.
712 */
713 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
714 throw new IllegalArgumentException("repeated interface: " + intf.getName());
715 }
716 }
717
718 for (Class<?> type : refTypes) {
719 ensureVisible(loader, type);
720 }
721 }
722
723 /*
724 * Returns all types referenced by all public non-static method signatures of
725 * the proxy interfaces
726 */
727 private static Set<Class<?>> referencedTypes(ClassLoader loader,
728 List<Class<?>> interfaces) {
729 var types = new HashSet<Class<?>>();
730 for (var intf : interfaces) {
731 for (Method m : intf.getMethods()) {
732 if (!Modifier.isStatic(m.getModifiers())) {
733 addElementType(types, m.getReturnType());
734 addElementTypes(types, m.getSharedParameterTypes());
735 addElementTypes(types, m.getSharedExceptionTypes());
736 }
737 }
738 }
739 return types;
740 }
741
742 private static void addElementTypes(HashSet<Class<?>> types,
743 Class<?> ... classes) {
744 for (var cls : classes) {
745 addElementType(types, cls);
746 }
747 }
748
749 private static void addElementType(HashSet<Class<?>> types,
750 Class<?> cls) {
751 var type = getElementType(cls);
752 if (!type.isPrimitive()) {
753 types.add(type);
754 }
755 }
756
757 /**
758 * Returns the context for the generated proxy class, including the
759 * module and the package it belongs to and whether it is package-private.
760 *
761 * If any of proxy interface is package-private, then the proxy class
762 * is in the same package and module as the package-private interface.
763 *
764 * If all proxy interfaces are public and in exported packages,
765 * then the proxy class is in a dynamic module in an unconditionally
766 * exported package.
767 *
768 * If all proxy interfaces are public and at least one in a non-exported
769 * package, then the proxy class is in a dynamic module in a
770 * non-exported package.
771 *
772 * The package of proxy class is open to java.base for deep reflective access.
773 *
774 * Reads edge and qualified exports are added for dynamic module to access.
775 */
776 private static ProxyClassContext proxyClassContext(ClassLoader loader,
777 List<Class<?>> interfaces,
778 Set<Class<?>> refTypes) {
779 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
780 boolean nonExported = false;
781
782 for (Class<?> intf : interfaces) {
783 Module m = intf.getModule();
784 if (!Modifier.isPublic(intf.getModifiers())) {
785 packagePrivateTypes.put(intf, m);
786 } else {
787 if (!intf.getModule().isExported(intf.getPackageName())) {
788 // module-private types
789 nonExported = true;
790 }
791 }
792 }
793
794 if (packagePrivateTypes.size() > 0) {
795 // all package-private types must be in the same runtime package
796 // i.e. same package name and same module (named or unnamed)
797 //
798 // Configuration will fail if M1 and in M2 defined by the same loader
799 // and both have the same package p (so no need to check class loader)
800 Module targetModule = null;
801 String targetPackageName = null;
802 for (Map.Entry<Class<?>, Module> e : packagePrivateTypes.entrySet()) {
803 Class<?> intf = e.getKey();
804 Module m = e.getValue();
805 if ((targetModule != null && targetModule != m) ||
806 (targetPackageName != null && targetPackageName != intf.getPackageName())) {
807 throw new IllegalArgumentException(
808 "cannot have non-public interfaces in different packages");
809 }
810 if (getLoader(m) != loader) {
811 // the specified loader is not the same class loader
812 // of the non-public interface
813 throw new IllegalArgumentException(
814 "non-public interface is not defined by the given loader");
815 }
816
817 targetModule = m;
818 targetPackageName = e.getKey().getPackageName();
819 }
820
821 // validate if the target module can access all other interfaces
822 for (Class<?> intf : interfaces) {
823 Module m = intf.getModule();
824 if (m == targetModule) continue;
825
826 if (!targetModule.canRead(m) || !m.isExported(intf.getPackageName(), targetModule)) {
827 throw new IllegalArgumentException(targetModule + " can't access " + intf.getName());
828 }
829 }
830
831 // opens the package of the non-public proxy class for java.base to access
832 if (targetModule.isNamed()) {
833 Modules.addOpens(targetModule, targetPackageName, Proxy.class.getModule());
834 }
835 // return the module of the package-private interface
836 return new ProxyClassContext(targetModule, targetPackageName, 0);
837 }
838
839 // All proxy interfaces are public. So maps to a dynamic proxy module
840 // and add reads edge and qualified exports, if necessary
841 Module targetModule = getDynamicModule(loader);
842
843 // set up proxy class access to proxy interfaces and types
844 // referenced in the method signature
845 Set<Class<?>> types = new HashSet<>(interfaces);
846 types.addAll(refTypes);
847 for (Class<?> c : types) {
848 ensureAccess(targetModule, c);
849 }
850
851 var pkgName = nonExported ? PROXY_PACKAGE_PREFIX + '.' + targetModule.getName()
852 : targetModule.getName();
853 return new ProxyClassContext(targetModule, pkgName, Modifier.PUBLIC);
854 }
855
856 /*
857 * Ensure the given module can access the given class.
858 */
859 private static void ensureAccess(Module target, Class<?> c) {
860 Module m = c.getModule();
861 // add read edge and qualified export for the target module to access
862 if (!target.canRead(m)) {
863 Modules.addReads(target, m);
864 }
865 String pn = c.getPackageName();
866 if (!m.isExported(pn, target)) {
867 Modules.addExports(m, pn, target);
868 }
869 }
870
871 /*
872 * Ensure the given class is visible to the class loader.
873 */
874 private static void ensureVisible(ClassLoader ld, Class<?> c) {
875 Class<?> type = null;
876 try {
877 type = Class.forName(c.getName(), false, ld);
878 } catch (ClassNotFoundException e) {
879 }
880 if (PrimitiveClass.asPrimaryType(type) != PrimitiveClass.asPrimaryType(c)) {
881 throw new IllegalArgumentException(c.getName() +
882 " referenced from a method is not visible from class loader: " + JLA.getLoaderNameID(ld));
883 }
884 }
885
886 private static Class<?> getElementType(Class<?> type) {
887 Class<?> e = type;
888 while (e.isArray()) {
889 e = e.getComponentType();
890 }
891 return e;
892 }
893
894 private static final ClassLoaderValue<Module> dynProxyModules =
895 new ClassLoaderValue<>();
896 private static final AtomicInteger counter = new AtomicInteger();
897
898 /*
899 * Define a dynamic module with a package named $MODULE which
900 * is unconditionally exported and another package named
901 * com.sun.proxy.$MODULE which is encapsulated.
902 *
903 * Each class loader will have one dynamic module.
904 */
905 private static Module getDynamicModule(ClassLoader loader) {
906 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> {
907 // create a dynamic module and setup module access
908 String mn = "jdk.proxy" + counter.incrementAndGet();
909 String pn = PROXY_PACKAGE_PREFIX + "." + mn;
910 ModuleDescriptor descriptor =
911 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC))
912 .packages(Set.of(pn, mn))
913 .exports(mn)
914 .build();
915 Module m = Modules.defineModule(ld, descriptor, null);
916 Modules.addReads(m, Proxy.class.getModule());
917 Modules.addExports(m, mn);
918 // java.base to create proxy instance and access its Lookup instance
919 Modules.addOpens(m, pn, Proxy.class.getModule());
920 Modules.addOpens(m, mn, Proxy.class.getModule());
921 return m;
922 });
923 }
924 }
925
926 /**
927 * Returns a proxy instance for the specified interfaces
928 * that dispatches method invocations to the specified invocation
929 * handler.
930 * <p>
931 * <a id="restrictions">{@code IllegalArgumentException} will be thrown
932 * if any of the following restrictions is violated:</a>
933 * <ul>
934 * <li>All of {@code Class} objects in the given {@code interfaces} array
935 * must represent {@linkplain Class#isHidden() non-hidden} and
936 * {@linkplain Class#isSealed() non-sealed} interfaces,
937 * not classes or primitive types.
938 *
939 * <li>No two elements in the {@code interfaces} array may
940 * refer to identical {@code Class} objects.
941 *
942 * <li>All of the interface types must be visible by name through the
943 * specified class loader. In other words, for class loader
944 * {@code cl} and every interface {@code i}, the following
945 * expression must be true:<p>
946 * {@code Class.forName(i.getName(), false, cl) == i}
947 *
948 * <li>All of the types referenced by all
949 * public method signatures of the specified interfaces
950 * and those inherited by their superinterfaces
951 * must be visible by name through the specified class loader.
952 *
953 * <li>All non-public interfaces must be in the same package
954 * and module, defined by the specified class loader and
955 * the module of the non-public interfaces can access all of
956 * the interface types; otherwise, it would not be possible for
957 * the proxy class to implement all of the interfaces,
958 * regardless of what package it is defined in.
959 *
960 * <li>For any set of member methods of the specified interfaces
961 * that have the same signature:
962 * <ul>
963 * <li>If the return type of any of the methods is a primitive
964 * type or void, then all of the methods must have that same
965 * return type.
966 * <li>Otherwise, one of the methods must have a return type that
967 * is assignable to all of the return types of the rest of the
968 * methods.
969 * </ul>
970 *
971 * <li>The resulting proxy class must not exceed any limits imposed
972 * on classes by the virtual machine. For example, the VM may limit
973 * the number of interfaces that a class may implement to 65535; in
974 * that case, the size of the {@code interfaces} array must not
975 * exceed 65535.
976 * </ul>
977 *
978 * <p>Note that the order of the specified proxy interfaces is
979 * significant: two requests for a proxy class with the same combination
980 * of interfaces but in a different order will result in two distinct
981 * proxy classes.
982 *
983 * @param loader the class loader to define the proxy class
984 * @param interfaces the list of interfaces for the proxy class
985 * to implement
986 * @param h the invocation handler to dispatch method invocations to
987 * @return a proxy instance with the specified invocation handler of a
988 * proxy class that is defined by the specified class loader
989 * and that implements the specified interfaces
990 * @throws IllegalArgumentException if any of the <a href="#restrictions">
991 * restrictions</a> on the parameters are violated
992 * @throws SecurityException if a security manager, <em>s</em>, is present
993 * and any of the following conditions is met:
994 * <ul>
995 * <li> the given {@code loader} is {@code null} and
996 * the caller's class loader is not {@code null} and the
997 * invocation of {@link SecurityManager#checkPermission
998 * s.checkPermission} with
999 * {@code RuntimePermission("getClassLoader")} permission
1000 * denies access;</li>
1001 * <li> for each proxy interface, {@code intf},
1002 * the caller's class loader is not the same as or an
1003 * ancestor of the class loader for {@code intf} and
1004 * invocation of {@link SecurityManager#checkPackageAccess
1005 * s.checkPackageAccess()} denies access to {@code intf};</li>
1006 * <li> any of the given proxy interfaces is non-public and the
1007 * caller class is not in the same {@linkplain Package runtime package}
1008 * as the non-public interface and the invocation of
1009 * {@link SecurityManager#checkPermission s.checkPermission} with
1010 * {@code ReflectPermission("newProxyInPackage.{package name}")}
1011 * permission denies access.</li>
1012 * </ul>
1013 * @throws NullPointerException if the {@code interfaces} array
1014 * argument or any of its elements are {@code null}, or
1015 * if the invocation handler, {@code h}, is
1016 * {@code null}
1017 *
1018 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
1019 * @revised 9
1020 */
1021 @CallerSensitive
1022 public static Object newProxyInstance(ClassLoader loader,
1023 Class<?>[] interfaces,
1024 InvocationHandler h) {
1025 Objects.requireNonNull(h);
1026
1027 @SuppressWarnings("removal")
1028 final Class<?> caller = System.getSecurityManager() == null
1029 ? null
1030 : Reflection.getCallerClass();
1031
1032 /*
1033 * Look up or generate the designated proxy class and its constructor.
1034 */
1035 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces);
1036
1037 return newProxyInstance(caller, cons, h);
1038 }
1039
1040 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager
1041 Constructor<?> cons,
1042 InvocationHandler h) {
1043 /*
1044 * Invoke its constructor with the designated invocation handler.
1045 */
1046 try {
1047 if (caller != null) {
1048 checkNewProxyPermission(caller, cons.getDeclaringClass());
1049 }
1050
1051 return cons.newInstance(new Object[]{h});
1052 } catch (IllegalAccessException | InstantiationException e) {
1053 throw new InternalError(e.toString(), e);
1054 } catch (InvocationTargetException e) {
1055 Throwable t = e.getCause();
1056 if (t instanceof RuntimeException re) {
1057 throw re;
1058 } else {
1059 throw new InternalError(t.toString(), t);
1060 }
1061 }
1062 }
1063
1064 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) {
1065 @SuppressWarnings("removal")
1066 SecurityManager sm = System.getSecurityManager();
1067 if (sm != null) {
1068 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
1069 ClassLoader ccl = caller.getClassLoader();
1070 ClassLoader pcl = proxyClass.getClassLoader();
1071
1072 // do permission check if the caller is in a different runtime package
1073 // of the proxy class
1074 String pkg = proxyClass.getPackageName();
1075 String callerPkg = caller.getPackageName();
1076
1077 if (pcl != ccl || !pkg.equals(callerPkg)) {
1078 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg));
1079 }
1080 }
1081 }
1082 }
1083
1084 /**
1085 * Returns the class loader for the given module.
1086 */
1087 @SuppressWarnings("removal")
1088 private static ClassLoader getLoader(Module m) {
1089 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
1090 return AccessController.doPrivileged(pa);
1091 }
1092
1093 /**
1094 * Returns true if the given class is a proxy class.
1095 *
1096 * @implNote The reliability of this method is important for the ability
1097 * to use it to make security decisions, so its implementation should
1098 * not just test if the class in question extends {@code Proxy}.
1099 *
1100 * @param cl the class to test
1101 * @return {@code true} if the class is a proxy class and
1102 * {@code false} otherwise
1103 * @throws NullPointerException if {@code cl} is {@code null}
1104 *
1105 * @revised 9
1106 */
1107 public static boolean isProxyClass(Class<?> cl) {
1108 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1109 }
1110
1111 /**
1112 * Returns the invocation handler for the specified proxy instance.
1113 *
1114 * @param proxy the proxy instance to return the invocation handler for
1115 * @return the invocation handler for the proxy instance
1116 * @throws IllegalArgumentException if the argument is not a
1117 * proxy instance
1118 * @throws SecurityException if a security manager, <em>s</em>, is present
1119 * and the caller's class loader is not the same as or an
1120 * ancestor of the class loader for the invocation handler
1121 * and invocation of {@link SecurityManager#checkPackageAccess
1122 * s.checkPackageAccess()} denies access to the invocation
1123 * handler's class.
1124 */
1125 @SuppressWarnings("removal")
1126 @CallerSensitive
1127 public static InvocationHandler getInvocationHandler(Object proxy)
1128 throws IllegalArgumentException
1129 {
1130 /*
1131 * Verify that the object is actually a proxy instance.
1132 */
1133 if (!isProxyClass(proxy.getClass())) {
1134 throw new IllegalArgumentException("not a proxy instance");
1135 }
1136
1137 final Proxy p = (Proxy) proxy;
1138 final InvocationHandler ih = p.h;
1139 if (System.getSecurityManager() != null) {
1140 Class<?> ihClass = ih.getClass();
1141 Class<?> caller = Reflection.getCallerClass();
1142 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1143 ihClass.getClassLoader()))
1144 {
1145 ReflectUtil.checkPackageAccess(ihClass);
1146 }
1147 }
1148
1149 return ih;
1150 }
1151
1152 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1153
1154 /**
1155 * A cache of Method -> MethodHandle for default methods.
1156 */
1157 private static final ClassValue<ConcurrentHashMap<Method, MethodHandle>>
1158 DEFAULT_METHODS_MAP = new ClassValue<>() {
1159 @Override
1160 protected ConcurrentHashMap<Method, MethodHandle> computeValue(Class<?> type) {
1161 return new ConcurrentHashMap<>(4);
1162 }
1163 };
1164
1165 private static ConcurrentHashMap<Method, MethodHandle> defaultMethodMap(Class<?> proxyClass) {
1166 assert isProxyClass(proxyClass);
1167 return DEFAULT_METHODS_MAP.get(proxyClass);
1168 }
1169
1170 static final Object[] EMPTY_ARGS = new Object[0];
1171
1172 static MethodHandle defaultMethodHandle(Class<? extends Proxy> proxyClass, Method method) {
1173 // lookup the cached method handle
1174 ConcurrentHashMap<Method, MethodHandle> methods = defaultMethodMap(proxyClass);
1175 MethodHandle superMH = methods.get(method);
1176 if (superMH == null) {
1177 MethodType type = methodType(method.getReturnType(), method.getParameterTypes());
1178 MethodHandles.Lookup lookup = MethodHandles.lookup();
1179 Class<?> proxyInterface = findProxyInterfaceOrElseThrow(proxyClass, method);
1180 MethodHandle dmh;
1181 try {
1182 dmh = proxyClassLookup(lookup, proxyClass)
1183 .findSpecial(proxyInterface, method.getName(), type, proxyClass)
1184 .withVarargs(false);
1185 } catch (IllegalAccessException | NoSuchMethodException e) {
1186 // should not reach here
1187 throw new InternalError(e);
1188 }
1189 // this check can be turned into assertion as it is guaranteed to succeed by the virtue of
1190 // looking up a default (instance) method declared or inherited by proxyInterface
1191 // while proxyClass implements (is a subtype of) proxyInterface ...
1192 assert ((BooleanSupplier) () -> {
1193 try {
1194 // make sure that the method type matches
1195 dmh.asType(type.insertParameterTypes(0, proxyClass));
1196 return true;
1197 } catch (WrongMethodTypeException e) {
1198 return false;
1199 }
1200 }).getAsBoolean() : "Wrong method type";
1201 // change return type to Object
1202 MethodHandle mh = dmh.asType(dmh.type().changeReturnType(Object.class));
1203 // wrap any exception thrown with InvocationTargetException
1204 mh = MethodHandles.catchException(mh, Throwable.class, InvocationException.wrapMH());
1205 // spread array of arguments among parameters (skipping 1st parameter - target)
1206 mh = mh.asSpreader(1, Object[].class, type.parameterCount());
1207 // change target type to Object
1208 mh = mh.asType(MethodType.methodType(Object.class, Object.class, Object[].class));
1209
1210 // push MH into cache
1211 MethodHandle cached = methods.putIfAbsent(method, mh);
1212 if (cached != null) {
1213 superMH = cached;
1214 } else {
1215 superMH = mh;
1216 }
1217 }
1218 return superMH;
1219 }
1220
1221 /**
1222 * Finds the first proxy interface that declares the given method
1223 * directly or indirectly.
1224 *
1225 * @throws IllegalArgumentException if not found
1226 */
1227 private static Class<?> findProxyInterfaceOrElseThrow(Class<?> proxyClass, Method method) {
1228 Class<?> declaringClass = method.getDeclaringClass();
1229 if (!declaringClass.isInterface()) {
1230 throw new IllegalArgumentException("\"" + method +
1231 "\" is not a method declared in the proxy class");
1232 }
1233
1234 List<Class<?>> proxyInterfaces = Arrays.asList(proxyClass.getInterfaces());
1235 // the method's declaring class is a proxy interface
1236 if (proxyInterfaces.contains(declaringClass))
1237 return declaringClass;
1238
1239 // find the first proxy interface that inherits the default method
1240 // i.e. the declaring class of the default method is a superinterface
1241 // of the proxy interface
1242 Deque<Class<?>> deque = new ArrayDeque<>();
1243 Set<Class<?>> visited = new HashSet<>();
1244 boolean indirectMethodRef = false;
1245 for (Class<?> proxyIntf : proxyInterfaces) {
1246 assert proxyIntf != declaringClass;
1247 visited.add(proxyIntf);
1248 deque.add(proxyIntf);
1249
1250 // for each proxy interface, traverse its subinterfaces with
1251 // breadth-first search to find a subinterface declaring the
1252 // default method
1253 Class<?> c;
1254 while ((c = deque.poll()) != null) {
1255 if (c == declaringClass) {
1256 try {
1257 // check if this method is the resolved method if referenced from
1258 // this proxy interface (i.e. this method is not implemented
1259 // by any other superinterface)
1260 Method m = proxyIntf.getMethod(method.getName(), method.getSharedParameterTypes());
1261 if (m.getDeclaringClass() == declaringClass) {
1262 return proxyIntf;
1263 }
1264 indirectMethodRef = true;
1265 } catch (NoSuchMethodException e) {}
1266
1267 // skip traversing its superinterfaces
1268 // another proxy interface may extend it and so
1269 // the method's declaring class is left unvisited.
1270 continue;
1271 }
1272 // visit all superinterfaces of one proxy interface to find if
1273 // this proxy interface inherits the method directly or indirectly
1274 visited.add(c);
1275 for (Class<?> superIntf : c.getInterfaces()) {
1276 if (!visited.contains(superIntf) && !deque.contains(superIntf)) {
1277 if (superIntf == declaringClass) {
1278 // fast-path as the matching subinterface is found
1279 deque.addFirst(superIntf);
1280 } else {
1281 deque.add(superIntf);
1282 }
1283 }
1284 }
1285 }
1286 }
1287
1288 throw new IllegalArgumentException("\"" + method + (indirectMethodRef
1289 ? "\" is overridden directly or indirectly by the proxy interfaces"
1290 : "\" is not a method declared in the proxy class"));
1291 }
1292
1293 /**
1294 * This method invokes the proxy's proxyClassLookup method to get a
1295 * Lookup on the proxy class.
1296 *
1297 * @return a lookup for proxy class of this proxy instance
1298 */
1299 @SuppressWarnings("removal")
1300 private static MethodHandles.Lookup proxyClassLookup(MethodHandles.Lookup caller, Class<?> proxyClass) {
1301 return AccessController.doPrivileged(new PrivilegedAction<>() {
1302 @Override
1303 public MethodHandles.Lookup run() {
1304 try {
1305 Method m = proxyClass.getDeclaredMethod("proxyClassLookup", MethodHandles.Lookup.class);
1306 m.setAccessible(true);
1307 return (MethodHandles.Lookup) m.invoke(null, caller);
1308 } catch (ReflectiveOperationException e) {
1309 throw new InternalError(e);
1310 }
1311 }
1312 });
1313 }
1314
1315 /*
1316 * Invoke the default method of the given proxy with an explicit caller class.
1317 *
1318 * @throws IllegalAccessException if the proxy interface is inaccessible to the caller
1319 * if caller is non-null
1320 */
1321 static Object invokeDefault(Object proxy, Method method, Object[] args, Class<?> caller)
1322 throws Throwable {
1323 // verify that the object is actually a proxy instance
1324 if (!Proxy.isProxyClass(proxy.getClass())) {
1325 throw new IllegalArgumentException("'proxy' is not a proxy instance");
1326 }
1327 if (!method.isDefault()) {
1328 throw new IllegalArgumentException("\"" + method + "\" is not a default method");
1329 }
1330 @SuppressWarnings("unchecked")
1331 Class<? extends Proxy> proxyClass = (Class<? extends Proxy>)proxy.getClass();
1332
1333 // skip access check if caller is null
1334 if (caller != null) {
1335 Class<?> intf = method.getDeclaringClass();
1336 // access check on the default method
1337 method.checkAccess(caller, intf, proxyClass, method.getModifiers());
1338 }
1339
1340 MethodHandle mh = Proxy.defaultMethodHandle(proxyClass, method);
1341 // invoke the super method
1342 try {
1343 // the args array can be null if the number of formal parameters required by
1344 // the method is zero (consistent with Method::invoke)
1345 Object[] params = args != null ? args : Proxy.EMPTY_ARGS;
1346 return mh.invokeExact(proxy, params);
1347 } catch (ClassCastException | NullPointerException e) {
1348 throw new IllegalArgumentException(e.getMessage(), e);
1349 } catch (Proxy.InvocationException e) {
1350 // unwrap and throw the exception thrown by the default method
1351 throw e.getCause();
1352 }
1353 }
1354
1355 /**
1356 * Internal exception type to wrap the exception thrown by the default method
1357 * so that it can distinguish CCE and NPE thrown due to the arguments
1358 * incompatible with the method signature.
1359 */
1360 static class InvocationException extends ReflectiveOperationException {
1361 @java.io.Serial
1362 private static final long serialVersionUID = 0L;
1363
1364 InvocationException(Throwable cause) {
1365 super(cause);
1366 }
1367
1368 /**
1369 * Wraps given cause with InvocationException and throws it.
1370 */
1371 static Object wrap(Throwable cause) throws InvocationException {
1372 throw new InvocationException(cause);
1373 }
1374
1375 @Stable
1376 static MethodHandle wrapMethodHandle;
1377
1378 static MethodHandle wrapMH() {
1379 MethodHandle mh = wrapMethodHandle;
1380 if (mh == null) {
1381 try {
1382 wrapMethodHandle = mh = MethodHandles.lookup().findStatic(
1383 InvocationException.class,
1384 "wrap",
1385 MethodType.methodType(Object.class, Throwable.class)
1386 );
1387 } catch (NoSuchMethodException | IllegalAccessException e) {
1388 throw new InternalError(e);
1389 }
1390 }
1391 return mh;
1392 }
1393 }
1394
1395 }