1 /*
2 * Copyright (c) 1999, 2022, 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.module.Modules;
54 import jdk.internal.misc.VM;
55 import jdk.internal.reflect.CallerSensitive;
56 import jdk.internal.reflect.Reflection;
57 import jdk.internal.loader.ClassLoaderValue;
58 import jdk.internal.vm.annotation.Stable;
59 import sun.reflect.misc.ReflectUtil;
60 import sun.security.action.GetPropertyAction;
61 import sun.security.util.SecurityConstants;
62
63 import static java.lang.invoke.MethodType.methodType;
64 import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC;
65
66 /**
67 *
68 * {@code Proxy} provides static methods for creating objects that act like instances
69 * of interfaces but allow for customized method invocation.
70 * To create a proxy instance for some interface {@code Foo}:
71 * <pre>{@code
72 * InvocationHandler handler = new MyInvocationHandler(...);
73 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
74 * new Class<?>[] { Foo.class },
75 * handler);
76 * }</pre>
77 *
78 * <p>
79 * A <em>proxy class</em> is a class created at runtime that implements a specified
80 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em>
81 * is an instance of a proxy class.
82 *
83 * Each proxy instance has an associated <i>invocation handler</i>
84 * object, which implements the interface {@link InvocationHandler}.
85 * A method invocation on a proxy instance through one of its proxy
86 * interfaces will be dispatched to the {@link InvocationHandler#invoke
87 * invoke} method of the instance's invocation handler, passing the proxy
88 * instance, a {@code java.lang.reflect.Method} object identifying
89 * the method that was invoked, and an array of type {@code Object}
90 * containing the arguments. The invocation handler processes the
91 * encoded method invocation as appropriate and the result that it
92 * returns will be returned as the result of the method invocation on
93 * the proxy instance.
94 *
95 * <p>A proxy class has the following properties:
96 *
97 * <ul>
98 * <li>The unqualified name of a proxy class is unspecified. The space
99 * of class names that begin with the string {@code "$Proxy"}
100 * should be, however, reserved for proxy classes.
101 *
102 * <li>The package and module in which a proxy class is defined is specified
103 * <a href="#membership">below</a>.
104 *
105 * <li>A proxy class is <em>final and non-abstract</em>.
106 *
107 * <li>A proxy class extends {@code java.lang.reflect.Proxy}.
108 *
109 * <li>A proxy class implements exactly the interfaces specified at its
110 * creation, in the same order. Invoking {@link Class#getInterfaces() getInterfaces}
111 * on its {@code Class} object will return an array containing the same
112 * list of interfaces (in the order specified at its creation), invoking
113 * {@link Class#getMethods getMethods} on its {@code Class} object will return
114 * an array of {@code Method} objects that include all of the
115 * methods in those interfaces, and invoking {@code getMethod} will
116 * find methods in the proxy interfaces as would be expected.
117 *
118 * <li>The {@link java.security.ProtectionDomain} of a proxy class
119 * is the same as that of system classes loaded by the bootstrap class
120 * loader, such as {@code java.lang.Object}, because the code for a
121 * proxy class is generated by trusted system code. This protection
122 * domain will typically be granted {@code java.security.AllPermission}.
123 *
124 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used
125 * to determine if a given class is a proxy class.
126 * </ul>
127 *
128 * <p>A proxy instance has the following properties:
129 *
130 * <ul>
131 * <li>Given a proxy instance {@code proxy} and one of the
132 * interfaces, {@code Foo}, implemented by its proxy class, the
133 * following expression will return true:
134 * <pre>
135 * {@code proxy instanceof Foo}
136 * </pre>
137 * and the following cast operation will succeed (rather than throwing
138 * a {@code ClassCastException}):
139 * <pre>
140 * {@code (Foo) proxy}
141 * </pre>
142 *
143 * <li>Each proxy instance has an associated invocation handler, the one
144 * that was passed to its constructor. The static
145 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method
146 * will return the invocation handler associated with the proxy instance
147 * passed as its argument.
148 *
149 * <li>An interface method invocation on a proxy instance will be
150 * encoded and dispatched to the invocation handler's {@link
151 * InvocationHandler#invoke invoke} method as described in the
152 * documentation for that method.
153 *
154 * <li>A proxy interface may define a default method or inherit
155 * a default method from its superinterface directly or indirectly.
156 * An invocation handler can invoke a default method of a proxy interface
157 * by calling {@link InvocationHandler#invokeDefault(Object, Method, Object...)
158 * InvocationHandler::invokeDefault}.
159 *
160 * <li>An invocation of the {@code hashCode},
161 * {@code equals}, or {@code toString} methods declared in
162 * {@code java.lang.Object} on a proxy instance will be encoded and
163 * dispatched to the invocation handler's {@code invoke} method in
164 * the same manner as interface method invocations are encoded and
165 * dispatched, as described above. The declaring class of the
166 * {@code Method} object passed to {@code invoke} will be
167 * {@code java.lang.Object}. Other public methods of a proxy
168 * instance inherited from {@code java.lang.Object} are not
169 * overridden by a proxy class, so invocations of those methods behave
170 * like they do for instances of {@code java.lang.Object}.
171 * </ul>
172 *
173 * <h2><a id="membership">Package and Module Membership of Proxy Class</a></h2>
174 *
175 * The package and module to which a proxy class belongs are chosen such that
176 * the accessibility of the proxy class is in line with the accessibility of
177 * the proxy interfaces. Specifically, the package and the module membership
178 * of a proxy class defined via the
179 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or
180 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)}
181 * methods is specified as follows:
182 *
183 * <ol>
184 * <li>If all the proxy interfaces are in <em>exported</em> or <em>open</em>
185 * packages:
186 * <ol type="a">
187 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
188 * <em>public</em> in an unconditionally exported but non-open package.
189 * The name of the package and the module are unspecified.</li>
190 *
191 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
192 * the proxy class is <em>non-public</em> in the package and module of the
193 * non-public interfaces. All the non-public interfaces must be in the same
194 * package and module; otherwise, proxying them is
195 * <a href="#restrictions">not possible</a>.</li>
196 * </ol>
197 * </li>
198 * <li>If at least one proxy interface is in a package that is
199 * <em>non-exported</em> and <em>non-open</em>:
200 * <ol type="a">
201 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is
202 * <em>public</em> in a <em>non-exported</em>, <em>non-open</em> package of
203 * <a href="#dynamicmodule"><em>dynamic module</em>.</a>
204 * The names of the package and the module are unspecified.</li>
205 *
206 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then
207 * the proxy class is <em>non-public</em> in the package and module of the
208 * non-public interfaces. All the non-public interfaces must be in the same
209 * package and module; otherwise, proxying them is
210 * <a href="#restrictions">not possible</a>.</li>
211 * </ol>
212 * </li>
213 * </ol>
214 *
215 * <p>
216 * Note that if proxy interfaces with a mix of accessibilities -- for example,
217 * an exported public interface and a non-exported non-public interface -- are
218 * proxied by the same instance, then the proxy class's accessibility is
219 * governed by the least accessible proxy interface.
220 * <p>
221 * Note that it is possible for arbitrary code to obtain access to a proxy class
222 * in an open package with {@link AccessibleObject#setAccessible setAccessible},
223 * whereas a proxy class in a non-open package is never accessible to
224 * code outside the module of the proxy class.
225 *
226 * <p>
227 * Throughout this specification, a "non-exported package" refers to a package
228 * that is not exported to all modules, and a "non-open package" refers to
229 * a package that is not open to all modules. Specifically, these terms refer to
230 * a package that either is not exported/open by its containing module or is
231 * exported/open in a qualified fashion by its containing module.
232 *
233 * <h3><a id="dynamicmodule">Dynamic Modules</a></h3>
234 * <p>
235 * A dynamic module is a named module generated at runtime. A proxy class
236 * defined in a dynamic module is encapsulated and not accessible to any module.
237 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in
238 * a dynamic module will throw {@code IllegalAccessException};
239 * {@code Proxy.newProxyInstance} method should be used instead.
240 *
241 * <p>
242 * A dynamic module can read the modules of all of the superinterfaces of a proxy
243 * class and the modules of the classes and interfaces referenced by
244 * all public method signatures of a proxy class. If a superinterface or
245 * a referenced class or interface, say {@code T}, is in a non-exported package,
246 * the {@linkplain Module module} of {@code T} is updated to export the
247 * package of {@code T} to the dynamic module.
248 *
249 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3>
250 *
251 * <p>When two or more proxy interfaces contain a method with
252 * the same name and parameter signature, the order of the proxy class's
253 * interfaces becomes significant. When such a <i>duplicate method</i>
254 * is invoked on a proxy instance, the {@code Method} object passed
255 * to the invocation handler will not necessarily be the one whose
256 * declaring class is assignable from the reference type of the interface
257 * that the proxy's method was invoked through. This limitation exists
258 * because the corresponding method implementation in the generated proxy
259 * class cannot determine which interface it was invoked through.
260 * Therefore, when a duplicate method is invoked on a proxy instance,
261 * the {@code Method} object for the method in the foremost interface
262 * that contains the method (either directly or inherited through a
263 * superinterface) in the proxy class's list of interfaces is passed to
264 * the invocation handler's {@code invoke} method, regardless of the
265 * reference type through which the method invocation occurred.
266 *
267 * <p>If a proxy interface contains a method with the same name and
268 * parameter signature as the {@code hashCode}, {@code equals},
269 * or {@code toString} methods of {@code java.lang.Object},
270 * when such a method is invoked on a proxy instance, the
271 * {@code Method} object passed to the invocation handler will have
272 * {@code java.lang.Object} as its declaring class. In other words,
273 * the public, non-final methods of {@code java.lang.Object}
274 * logically precede all of the proxy interfaces for the determination of
275 * which {@code Method} object to pass to the invocation handler.
276 *
277 * <p>Note also that when a duplicate method is dispatched to an
278 * invocation handler, the {@code invoke} method may only throw
279 * checked exception types that are assignable to one of the exception
280 * types in the {@code throws} clause of the method in <i>all</i> of
281 * the proxy interfaces that it can be invoked through. If the
282 * {@code invoke} method throws a checked exception that is not
283 * assignable to any of the exception types declared by the method in one
284 * of the proxy interfaces that it can be invoked through, then an
285 * unchecked {@code UndeclaredThrowableException} will be thrown by
286 * the invocation on the proxy instance. This restriction means that not
287 * all of the exception types returned by invoking
288 * {@code getExceptionTypes} on the {@code Method} object
289 * passed to the {@code invoke} method can necessarily be thrown
290 * successfully by the {@code invoke} method.
291 *
292 * @author Peter Jones
293 * @see InvocationHandler
294 * @since 1.3
295 * @revised 9
296 */
297 public class Proxy implements java.io.Serializable {
298 @java.io.Serial
299 private static final long serialVersionUID = -2222568056686623797L;
300
301 /** parameter types of a proxy class constructor */
302 private static final Class<?>[] constructorParams =
303 { InvocationHandler.class };
304
305 /**
306 * a cache of proxy constructors with
307 * {@link Constructor#setAccessible(boolean) accessible} flag already set
308 */
309 private static final ClassLoaderValue<Constructor<?>> proxyCache =
310 new ClassLoaderValue<>();
311
312 /**
313 * the invocation handler for this proxy instance.
314 * @serial
315 */
316 @SuppressWarnings("serial") // Not statically typed as Serializable
317 protected InvocationHandler h;
318
319 /**
320 * Prohibits instantiation.
321 */
322 private Proxy() {
323 }
324
325 /**
326 * Constructs a new {@code Proxy} instance from a subclass
327 * (typically, a dynamic proxy class) with the specified value
328 * for its invocation handler.
329 *
330 * @param h the invocation handler for this proxy instance
331 *
332 * @throws NullPointerException if the given invocation handler, {@code h},
333 * is {@code null}.
334 */
335 protected Proxy(InvocationHandler h) {
336 Objects.requireNonNull(h);
337 this.h = h;
338 }
339
340 /**
341 * Returns the {@code java.lang.Class} object for a proxy class
342 * given a class loader and an array of interfaces. The proxy class
343 * will be defined by the specified class loader and will implement
344 * all of the supplied interfaces. If any of the given interfaces
345 * is non-public, the proxy class will be non-public. If a proxy class
346 * for the same permutation of interfaces has already been defined by the
347 * class loader, then the existing proxy class will be returned; otherwise,
348 * a proxy class for those interfaces will be generated dynamically
349 * and defined by the class loader.
350 *
351 * @param loader the class loader to define the proxy class
352 * @param interfaces the list of interfaces for the proxy class
353 * to implement
354 * @return a proxy class that is defined in the specified class loader
355 * and that implements the specified interfaces
356 * @throws IllegalArgumentException if any of the <a href="#restrictions">
357 * restrictions</a> on the parameters are violated
358 * @throws SecurityException if a security manager, <em>s</em>, is present
359 * and any of the following conditions is met:
360 * <ul>
361 * <li> the given {@code loader} is {@code null} and
362 * the caller's class loader is not {@code null} and the
363 * invocation of {@link SecurityManager#checkPermission
364 * s.checkPermission} with
365 * {@code RuntimePermission("getClassLoader")} permission
366 * denies access.</li>
367 * <li> for each proxy interface, {@code intf},
368 * the caller's class loader is not the same as or an
369 * ancestor of the class loader for {@code intf} and
370 * invocation of {@link SecurityManager#checkPackageAccess
371 * s.checkPackageAccess()} denies access to {@code intf}.</li>
372 * </ul>
373 * @throws NullPointerException if the {@code interfaces} array
374 * argument or any of its elements are {@code null}
375 *
376 * @deprecated Proxy classes generated in a named module are encapsulated
377 * and not accessible to code outside its module.
378 * {@link Constructor#newInstance(Object...) Constructor.newInstance}
379 * will throw {@code IllegalAccessException} when it is called on
380 * an inaccessible proxy class.
381 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
382 * to create a proxy instance instead.
383 *
384 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
385 * @revised 9
386 */
387 @Deprecated
388 @CallerSensitive
389 public static Class<?> getProxyClass(ClassLoader loader,
390 Class<?>... interfaces)
391 throws IllegalArgumentException
392 {
393 @SuppressWarnings("removal")
394 Class<?> caller = System.getSecurityManager() == null
395 ? null
396 : Reflection.getCallerClass();
397
398 return getProxyConstructor(caller, loader, interfaces)
399 .getDeclaringClass();
400 }
401
402 /**
403 * Returns the {@code Constructor} object of a proxy class that takes a
404 * single argument of type {@link InvocationHandler}, given a class loader
405 * and an array of interfaces. The returned constructor will have the
406 * {@link Constructor#setAccessible(boolean) accessible} flag already set.
407 *
408 * @param caller passed from a public-facing @CallerSensitive method if
409 * SecurityManager is set or {@code null} if there's no
410 * SecurityManager
411 * @param loader the class loader to define the proxy class
412 * @param interfaces the list of interfaces for the proxy class
413 * to implement
414 * @return a Constructor of the proxy class taking single
415 * {@code InvocationHandler} parameter
416 */
417 private static Constructor<?> getProxyConstructor(Class<?> caller,
418 ClassLoader loader,
419 Class<?>... interfaces)
420 {
421 // optimization for single interface
422 if (interfaces.length == 1) {
423 Class<?> intf = interfaces[0];
424 if (caller != null) {
425 checkProxyAccess(caller, loader, intf);
426 }
427 return proxyCache.sub(intf).computeIfAbsent(
428 loader,
429 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
430 );
431 } else {
432 // interfaces cloned
433 final Class<?>[] intfsArray = interfaces.clone();
434 if (caller != null) {
435 checkProxyAccess(caller, loader, intfsArray);
436 }
437 final List<Class<?>> intfs = Arrays.asList(intfsArray);
438 return proxyCache.sub(intfs).computeIfAbsent(
439 loader,
440 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
441 );
442 }
443 }
444
445 /*
446 * Check permissions required to create a Proxy class.
447 *
448 * To define a proxy class, it performs the access checks as in
449 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
450 * 1. "getClassLoader" permission check if loader == null
451 * 2. checkPackageAccess on the interfaces it implements
452 *
453 * To get a constructor and new instance of a proxy class, it performs
454 * the package access check on the interfaces it implements
455 * as in Class.getConstructor.
456 *
457 * If an interface is non-public, the proxy class must be defined by
458 * the defining loader of the interface. If the caller's class loader
459 * is not the same as the defining loader of the interface, the VM
460 * will throw IllegalAccessError when the generated proxy class is
461 * being defined.
462 */
463 private static void checkProxyAccess(Class<?> caller,
464 ClassLoader loader,
465 Class<?> ... interfaces)
466 {
467 @SuppressWarnings("removal")
468 SecurityManager sm = System.getSecurityManager();
469 if (sm != null) {
470 ClassLoader ccl = caller.getClassLoader();
471 if (loader == null && ccl != null) {
472 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
473 }
474 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
475 }
476 }
477
478 /**
479 * Builder for a proxy class.
480 *
481 * If the module is not specified in this ProxyBuilder constructor,
482 * it will map from the given loader and interfaces to the module
483 * in which the proxy class will be defined.
484 */
485 private static final class ProxyBuilder {
486 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
487
488 // prefix for all proxy class names
489 private static final String proxyClassNamePrefix = "$Proxy";
490
491 // next number to use for generation of unique proxy class names
492 private static final AtomicLong nextUniqueNumber = new AtomicLong();
493
494 // a reverse cache of defined proxy classes
495 private static final ClassLoaderValue<Boolean> reverseProxyCache =
496 new ClassLoaderValue<>();
497
498 private record ProxyClassContext(Module module, String packageName, int accessFlags) {
499 private ProxyClassContext {
500 if (module.isNamed()) {
501 if (packageName.isEmpty()) {
502 // Per JLS 7.4.2, unnamed package can only exist in unnamed modules.
503 // This means a package-private superinterface exist in the unnamed
504 // package of a named module.
505 throw new InternalError("Unnamed package cannot be added to " + module);
506 }
507
508 if (!module.getDescriptor().packages().contains(packageName)) {
509 throw new InternalError(packageName + " not exist in " + module.getName());
510 }
511
512 if (!module.isOpen(packageName, Proxy.class.getModule())) {
513 // Required for default method invocation
514 throw new InternalError(packageName + " not open to " + Proxy.class.getModule());
515 }
516 } else {
517 if (Modifier.isPublic(accessFlags)) {
518 // All proxy superinterfaces are public, must be in named dynamic module
519 throw new InternalError("public proxy in unnamed module: " + module);
520 }
521 }
522
523 if ((accessFlags & ~Modifier.PUBLIC) != 0) {
524 throw new InternalError("proxy access flags must be Modifier.PUBLIC or 0");
525 }
526 }
527 }
528
529 private static Class<?> defineProxyClass(ProxyClassContext context, List<Class<?>> interfaces) {
530 /*
531 * Choose a name for the proxy class to generate.
532 */
533 long num = nextUniqueNumber.getAndIncrement();
534 String proxyName = context.packageName().isEmpty()
535 ? proxyClassNamePrefix + num
536 : context.packageName() + "." + proxyClassNamePrefix + num;
537
538 ClassLoader loader = getLoader(context.module());
539 trace(proxyName, context.module(), loader, interfaces);
540
541 /*
542 * Generate the specified proxy class.
543 */
544 byte[] proxyClassFile = ProxyGenerator.generateProxyClass(loader, proxyName, interfaces,
545 context.accessFlags() | Modifier.FINAL);
546 try {
547 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
548 null, "__dynamic_proxy__");
549 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
550 return pc;
551 } catch (ClassFormatError e) {
552 /*
553 * A ClassFormatError here means that (barring bugs in the
554 * proxy class generation code) there was some other
555 * invalid aspect of the arguments supplied to the proxy
556 * class creation (such as virtual machine limitations
557 * exceeded).
558 */
559 throw new IllegalArgumentException(e.toString());
560 }
561 }
562
563 /**
564 * Test if given class is a class defined by
565 * {@link #defineProxyClass(ProxyClassContext, List)}
566 */
567 static boolean isProxyClass(Class<?> c) {
568 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()),
569 Boolean.TRUE);
570 }
571
572 private static boolean isExportedType(Class<?> c) {
573 String pn = c.getPackageName();
574 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
575 }
576
577 private static boolean isPackagePrivateType(Class<?> c) {
578 return !Modifier.isPublic(c.getModifiers());
579 }
580
581 private static String toDetails(Class<?> c) {
582 String access = "unknown";
583 if (isExportedType(c)) {
584 access = "exported";
585 } else if (isPackagePrivateType(c)) {
586 access = "package-private";
587 } else {
588 access = "module-private";
589 }
590 ClassLoader ld = c.getClassLoader();
591 return String.format(" %s/%s %s loader %s",
592 c.getModule().getName(), c.getName(), access, ld);
593 }
594
595 static void trace(String cn,
596 Module module,
597 ClassLoader loader,
598 List<Class<?>> interfaces) {
599 if (isDebug()) {
600 System.err.format("PROXY: %s/%s defined by %s%n",
601 module.getName(), cn, loader);
602 }
603 if (isDebug("debug")) {
604 interfaces.forEach(c -> System.out.println(toDetails(c)));
605 }
606 }
607
608 private static final String DEBUG =
609 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", "");
610
611 private static boolean isDebug() {
612 return !DEBUG.isEmpty();
613 }
614 private static boolean isDebug(String flag) {
615 return DEBUG.equals(flag);
616 }
617
618 // ProxyBuilder instance members start here....
619
620 private final List<Class<?>> interfaces;
621 private final ProxyClassContext context;
622 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
623 if (!VM.isModuleSystemInited()) {
624 throw new InternalError("Proxy is not supported until "
625 + "module system is fully initialized");
626 }
627 if (interfaces.size() > 65535) {
628 throw new IllegalArgumentException("interface limit exceeded: "
629 + interfaces.size());
630 }
631
632 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
633
634 // IAE if violates any restrictions specified in newProxyInstance
635 validateProxyInterfaces(loader, interfaces, refTypes);
636
637 this.interfaces = interfaces;
638 this.context = proxyClassContext(loader, interfaces, refTypes);
639 assert getLoader(context.module()) == loader;
640 }
641
642 ProxyBuilder(ClassLoader loader, Class<?> intf) {
643 this(loader, Collections.singletonList(intf));
644 }
645
646 /**
647 * Generate a proxy class and return its proxy Constructor with
648 * accessible flag already set. If the target module does not have access
649 * to any interface types, IllegalAccessError will be thrown by the VM
650 * at defineClass time.
651 *
652 * Must call the checkProxyAccess method to perform permission checks
653 * before calling this.
654 */
655 @SuppressWarnings("removal")
656 Constructor<?> build() {
657 Class<?> proxyClass = defineProxyClass(context, interfaces);
658
659 final Constructor<?> cons;
660 try {
661 cons = proxyClass.getConstructor(constructorParams);
662 } catch (NoSuchMethodException e) {
663 throw new InternalError(e.toString(), e);
664 }
665 AccessController.doPrivileged(new PrivilegedAction<Void>() {
666 public Void run() {
667 cons.setAccessible(true);
668 return null;
669 }
670 });
671 return cons;
672 }
673
674 /**
675 * Validate the given proxy interfaces and the given referenced types
676 * are visible to the defining loader.
677 *
678 * @throws IllegalArgumentException if it violates the restrictions
679 * specified in {@link Proxy#newProxyInstance}
680 */
681 private static void validateProxyInterfaces(ClassLoader loader,
682 List<Class<?>> interfaces,
683 Set<Class<?>> refTypes)
684 {
685 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
686 for (Class<?> intf : interfaces) {
687 /*
688 * Verify that the Class object actually represents an
689 * interface.
690 */
691 if (!intf.isInterface()) {
692 throw new IllegalArgumentException(intf.getName() + " is not an interface");
693 }
694
695 if (intf.isHidden()) {
696 throw new IllegalArgumentException(intf.getName() + " is a hidden interface");
697 }
698
699 if (intf.isSealed()) {
700 throw new IllegalArgumentException(intf.getName() + " is a sealed interface");
701 }
702
703 /*
704 * Verify that the class loader resolves the name of this
705 * interface to the same Class object.
706 */
707 ensureVisible(loader, intf);
708
709 /*
710 * Verify that this interface is not a duplicate.
711 */
712 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
713 throw new IllegalArgumentException("repeated interface: " + intf.getName());
714 }
715 }
716
717 for (Class<?> type : refTypes) {
718 ensureVisible(loader, type);
719 }
720 }
721
722 /*
723 * Returns all types referenced by all public non-static method signatures of
724 * the proxy interfaces
725 */
726 private static Set<Class<?>> referencedTypes(ClassLoader loader,
727 List<Class<?>> interfaces) {
728 var types = new HashSet<Class<?>>();
729 for (var intf : interfaces) {
730 for (Method m : intf.getMethods()) {
731 if (!Modifier.isStatic(m.getModifiers())) {
732 addElementType(types, m.getReturnType());
733 addElementTypes(types, m.getSharedParameterTypes());
734 addElementTypes(types, m.getSharedExceptionTypes());
735 }
736 }
737 }
738 return types;
739 }
740
741 private static void addElementTypes(HashSet<Class<?>> types,
742 Class<?> ... classes) {
743 for (var cls : classes) {
744 addElementType(types, cls);
745 }
746 }
747
748 private static void addElementType(HashSet<Class<?>> types,
749 Class<?> cls) {
750 var type = getElementType(cls);
751 if (!type.isPrimitive()) {
752 types.add(type);
753 }
754 }
755
756 /**
757 * Returns the context for the generated proxy class, including the
758 * module and the package it belongs to and whether it is package-private.
759 *
760 * If any of proxy interface is package-private, then the proxy class
761 * is in the same package and module as the package-private interface.
762 *
763 * If all proxy interfaces are public and in exported packages,
764 * then the proxy class is in a dynamic module in an unconditionally
765 * exported package.
766 *
767 * If all proxy interfaces are public and at least one in a non-exported
768 * package, then the proxy class is in a dynamic module in a
769 * non-exported package.
770 *
771 * The package of proxy class is open to java.base for deep reflective access.
772 *
773 * Reads edge and qualified exports are added for dynamic module to access.
774 */
775 private static ProxyClassContext proxyClassContext(ClassLoader loader,
776 List<Class<?>> interfaces,
777 Set<Class<?>> refTypes) {
778 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
779 boolean nonExported = false;
780
781 for (Class<?> intf : interfaces) {
782 Module m = intf.getModule();
783 if (!Modifier.isPublic(intf.getModifiers())) {
784 packagePrivateTypes.put(intf, m);
785 } else {
786 if (!intf.getModule().isExported(intf.getPackageName())) {
787 // module-private types
788 nonExported = true;
789 }
790 }
791 }
792
793 if (packagePrivateTypes.size() > 0) {
794 // all package-private types must be in the same runtime package
795 // i.e. same package name and same module (named or unnamed)
796 //
797 // Configuration will fail if M1 and in M2 defined by the same loader
798 // and both have the same package p (so no need to check class loader)
799 Module targetModule = null;
800 String targetPackageName = null;
801 for (Map.Entry<Class<?>, Module> e : packagePrivateTypes.entrySet()) {
802 Class<?> intf = e.getKey();
803 Module m = e.getValue();
804 if ((targetModule != null && targetModule != m) ||
805 (targetPackageName != null && targetPackageName != intf.getPackageName())) {
806 throw new IllegalArgumentException(
807 "cannot have non-public interfaces in different packages");
808 }
809 if (getLoader(m) != loader) {
810 // the specified loader is not the same class loader
811 // of the non-public interface
812 throw new IllegalArgumentException(
813 "non-public interface is not defined by the given loader");
814 }
815
816 targetModule = m;
817 targetPackageName = e.getKey().getPackageName();
818 }
819
820 // validate if the target module can access all other interfaces
821 for (Class<?> intf : interfaces) {
822 Module m = intf.getModule();
823 if (m == targetModule) continue;
824
825 if (!targetModule.canRead(m) || !m.isExported(intf.getPackageName(), targetModule)) {
826 throw new IllegalArgumentException(targetModule + " can't access " + intf.getName());
827 }
828 }
829
830 // opens the package of the non-public proxy class for java.base to access
831 if (targetModule.isNamed()) {
832 Modules.addOpens(targetModule, targetPackageName, Proxy.class.getModule());
833 }
834 // return the module of the package-private interface
835 return new ProxyClassContext(targetModule, targetPackageName, 0);
836 }
837
838 // All proxy interfaces are public. So maps to a dynamic proxy module
839 // and add reads edge and qualified exports, if necessary
840 Module targetModule = getDynamicModule(loader);
841
842 // set up proxy class access to proxy interfaces and types
843 // referenced in the method signature
844 Set<Class<?>> types = new HashSet<>(interfaces);
845 types.addAll(refTypes);
846 for (Class<?> c : types) {
847 ensureAccess(targetModule, c);
848 }
849
850 var pkgName = nonExported ? PROXY_PACKAGE_PREFIX + '.' + targetModule.getName()
851 : targetModule.getName();
852 return new ProxyClassContext(targetModule, pkgName, Modifier.PUBLIC);
853 }
854
855 /*
856 * Ensure the given module can access the given class.
857 */
858 private static void ensureAccess(Module target, Class<?> c) {
859 Module m = c.getModule();
860 // add read edge and qualified export for the target module to access
861 if (!target.canRead(m)) {
862 Modules.addReads(target, m);
863 }
864 String pn = c.getPackageName();
865 if (!m.isExported(pn, target)) {
866 Modules.addExports(m, pn, target);
867 }
868 }
869
870 /*
871 * Ensure the given class is visible to the class loader.
872 */
873 private static void ensureVisible(ClassLoader ld, Class<?> c) {
874 Class<?> type = null;
875 try {
876 type = Class.forName(c.getName(), false, ld);
877 } catch (ClassNotFoundException e) {
878 }
879 if (type != c) {
880 throw new IllegalArgumentException(c.getName() +
881 " referenced from a method is not visible from class loader");
882 }
883 }
884
885 private static Class<?> getElementType(Class<?> type) {
886 Class<?> e = type;
887 while (e.isArray()) {
888 e = e.getComponentType();
889 }
890 return e;
891 }
892
893 private static final ClassLoaderValue<Module> dynProxyModules =
894 new ClassLoaderValue<>();
895 private static final AtomicInteger counter = new AtomicInteger();
896
897 /*
898 * Define a dynamic module with a package named $MODULE which
899 * is unconditionally exported and another package named
900 * com.sun.proxy.$MODULE which is encapsulated.
901 *
902 * Each class loader will have one dynamic module.
903 */
904 private static Module getDynamicModule(ClassLoader loader) {
905 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> {
906 // create a dynamic module and setup module access
907 String mn = "jdk.proxy" + counter.incrementAndGet();
908 String pn = PROXY_PACKAGE_PREFIX + "." + mn;
909 ModuleDescriptor descriptor =
910 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC))
911 .packages(Set.of(pn, mn))
912 .exports(mn)
913 .build();
914 Module m = Modules.defineModule(ld, descriptor, null);
915 Modules.addReads(m, Proxy.class.getModule());
916 Modules.addExports(m, mn);
917 // java.base to create proxy instance and access its Lookup instance
918 Modules.addOpens(m, pn, Proxy.class.getModule());
919 Modules.addOpens(m, mn, Proxy.class.getModule());
920 return m;
921 });
922 }
923 }
924
925 /**
926 * Returns a proxy instance for the specified interfaces
927 * that dispatches method invocations to the specified invocation
928 * handler.
929 * <p>
930 * <a id="restrictions">{@code IllegalArgumentException} will be thrown
931 * if any of the following restrictions is violated:</a>
932 * <ul>
933 * <li>All of {@code Class} objects in the given {@code interfaces} array
934 * must represent {@linkplain Class#isHidden() non-hidden} and
935 * {@linkplain Class#isSealed() non-sealed} interfaces,
936 * not classes or primitive types.
937 *
938 * <li>No two elements in the {@code interfaces} array may
939 * refer to identical {@code Class} objects.
940 *
941 * <li>All of the interface types must be visible by name through the
942 * specified class loader. In other words, for class loader
943 * {@code cl} and every interface {@code i}, the following
944 * expression must be true:<p>
945 * {@code Class.forName(i.getName(), false, cl) == i}
946 *
947 * <li>All of the types referenced by all
948 * public method signatures of the specified interfaces
949 * and those inherited by their superinterfaces
950 * must be visible by name through the specified class loader.
951 *
952 * <li>All non-public interfaces must be in the same package
953 * and module, defined by the specified class loader and
954 * the module of the non-public interfaces can access all of
955 * the interface types; otherwise, it would not be possible for
956 * the proxy class to implement all of the interfaces,
957 * regardless of what package it is defined in.
958 *
959 * <li>For any set of member methods of the specified interfaces
960 * that have the same signature:
961 * <ul>
962 * <li>If the return type of any of the methods is a primitive
963 * type or void, then all of the methods must have that same
964 * return type.
965 * <li>Otherwise, one of the methods must have a return type that
966 * is assignable to all of the return types of the rest of the
967 * methods.
968 * </ul>
969 *
970 * <li>The resulting proxy class must not exceed any limits imposed
971 * on classes by the virtual machine. For example, the VM may limit
972 * the number of interfaces that a class may implement to 65535; in
973 * that case, the size of the {@code interfaces} array must not
974 * exceed 65535.
975 * </ul>
976 *
977 * <p>Note that the order of the specified proxy interfaces is
978 * significant: two requests for a proxy class with the same combination
979 * of interfaces but in a different order will result in two distinct
980 * proxy classes.
981 *
982 * @param loader the class loader to define the proxy class
983 * @param interfaces the list of interfaces for the proxy class
984 * to implement
985 * @param h the invocation handler to dispatch method invocations to
986 * @return a proxy instance with the specified invocation handler of a
987 * proxy class that is defined by the specified class loader
988 * and that implements the specified interfaces
989 * @throws IllegalArgumentException if any of the <a href="#restrictions">
990 * restrictions</a> on the parameters are violated
991 * @throws SecurityException if a security manager, <em>s</em>, is present
992 * and any of the following conditions is met:
993 * <ul>
994 * <li> the given {@code loader} is {@code null} and
995 * the caller's class loader is not {@code null} and the
996 * invocation of {@link SecurityManager#checkPermission
997 * s.checkPermission} with
998 * {@code RuntimePermission("getClassLoader")} permission
999 * denies access;</li>
1000 * <li> for each proxy interface, {@code intf},
1001 * the caller's class loader is not the same as or an
1002 * ancestor of the class loader for {@code intf} and
1003 * invocation of {@link SecurityManager#checkPackageAccess
1004 * s.checkPackageAccess()} denies access to {@code intf};</li>
1005 * <li> any of the given proxy interfaces is non-public and the
1006 * caller class is not in the same {@linkplain Package runtime package}
1007 * as the non-public interface and the invocation of
1008 * {@link SecurityManager#checkPermission s.checkPermission} with
1009 * {@code ReflectPermission("newProxyInPackage.{package name}")}
1010 * permission denies access.</li>
1011 * </ul>
1012 * @throws NullPointerException if the {@code interfaces} array
1013 * argument or any of its elements are {@code null}, or
1014 * if the invocation handler, {@code h}, is
1015 * {@code null}
1016 *
1017 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
1018 * @revised 9
1019 */
1020 @CallerSensitive
1021 public static Object newProxyInstance(ClassLoader loader,
1022 Class<?>[] interfaces,
1023 InvocationHandler h) {
1024 Objects.requireNonNull(h);
1025
1026 @SuppressWarnings("removal")
1027 final Class<?> caller = System.getSecurityManager() == null
1028 ? null
1029 : Reflection.getCallerClass();
1030
1031 /*
1032 * Look up or generate the designated proxy class and its constructor.
1033 */
1034 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces);
1035
1036 return newProxyInstance(caller, cons, h);
1037 }
1038
1039 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager
1040 Constructor<?> cons,
1041 InvocationHandler h) {
1042 /*
1043 * Invoke its constructor with the designated invocation handler.
1044 */
1045 try {
1046 if (caller != null) {
1047 checkNewProxyPermission(caller, cons.getDeclaringClass());
1048 }
1049
1050 return cons.newInstance(new Object[]{h});
1051 } catch (IllegalAccessException | InstantiationException e) {
1052 throw new InternalError(e.toString(), e);
1053 } catch (InvocationTargetException e) {
1054 Throwable t = e.getCause();
1055 if (t instanceof RuntimeException) {
1056 throw (RuntimeException) t;
1057 } else {
1058 throw new InternalError(t.toString(), t);
1059 }
1060 }
1061 }
1062
1063 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) {
1064 @SuppressWarnings("removal")
1065 SecurityManager sm = System.getSecurityManager();
1066 if (sm != null) {
1067 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
1068 ClassLoader ccl = caller.getClassLoader();
1069 ClassLoader pcl = proxyClass.getClassLoader();
1070
1071 // do permission check if the caller is in a different runtime package
1072 // of the proxy class
1073 String pkg = proxyClass.getPackageName();
1074 String callerPkg = caller.getPackageName();
1075
1076 if (pcl != ccl || !pkg.equals(callerPkg)) {
1077 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg));
1078 }
1079 }
1080 }
1081 }
1082
1083 /**
1084 * Returns the class loader for the given module.
1085 */
1086 @SuppressWarnings("removal")
1087 private static ClassLoader getLoader(Module m) {
1088 PrivilegedAction<ClassLoader> pa = m::getClassLoader;
1089 return AccessController.doPrivileged(pa);
1090 }
1091
1092 /**
1093 * Returns true if the given class is a proxy class.
1094 *
1095 * @implNote The reliability of this method is important for the ability
1096 * to use it to make security decisions, so its implementation should
1097 * not just test if the class in question extends {@code Proxy}.
1098 *
1099 * @param cl the class to test
1100 * @return {@code true} if the class is a proxy class and
1101 * {@code false} otherwise
1102 * @throws NullPointerException if {@code cl} is {@code null}
1103 *
1104 * @revised 9
1105 */
1106 public static boolean isProxyClass(Class<?> cl) {
1107 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1108 }
1109
1110 /**
1111 * Returns the invocation handler for the specified proxy instance.
1112 *
1113 * @param proxy the proxy instance to return the invocation handler for
1114 * @return the invocation handler for the proxy instance
1115 * @throws IllegalArgumentException if the argument is not a
1116 * proxy instance
1117 * @throws SecurityException if a security manager, <em>s</em>, is present
1118 * and the caller's class loader is not the same as or an
1119 * ancestor of the class loader for the invocation handler
1120 * and invocation of {@link SecurityManager#checkPackageAccess
1121 * s.checkPackageAccess()} denies access to the invocation
1122 * handler's class.
1123 */
1124 @SuppressWarnings("removal")
1125 @CallerSensitive
1126 public static InvocationHandler getInvocationHandler(Object proxy)
1127 throws IllegalArgumentException
1128 {
1129 /*
1130 * Verify that the object is actually a proxy instance.
1131 */
1132 if (!isProxyClass(proxy.getClass())) {
1133 throw new IllegalArgumentException("not a proxy instance");
1134 }
1135
1136 final Proxy p = (Proxy) proxy;
1137 final InvocationHandler ih = p.h;
1138 if (System.getSecurityManager() != null) {
1139 Class<?> ihClass = ih.getClass();
1140 Class<?> caller = Reflection.getCallerClass();
1141 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1142 ihClass.getClassLoader()))
1143 {
1144 ReflectUtil.checkPackageAccess(ihClass);
1145 }
1146 }
1147
1148 return ih;
1149 }
1150
1151 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1152
1153 /**
1154 * A cache of Method -> MethodHandle for default methods.
1155 */
1156 private static final ClassValue<ConcurrentHashMap<Method, MethodHandle>>
1157 DEFAULT_METHODS_MAP = new ClassValue<>() {
1158 @Override
1159 protected ConcurrentHashMap<Method, MethodHandle> computeValue(Class<?> type) {
1160 return new ConcurrentHashMap<>(4);
1161 }
1162 };
1163
1164 private static ConcurrentHashMap<Method, MethodHandle> defaultMethodMap(Class<?> proxyClass) {
1165 assert isProxyClass(proxyClass);
1166 return DEFAULT_METHODS_MAP.get(proxyClass);
1167 }
1168
1169 static final Object[] EMPTY_ARGS = new Object[0];
1170
1171 static MethodHandle defaultMethodHandle(Class<? extends Proxy> proxyClass, Method method) {
1172 // lookup the cached method handle
1173 ConcurrentHashMap<Method, MethodHandle> methods = defaultMethodMap(proxyClass);
1174 MethodHandle superMH = methods.get(method);
1175 if (superMH == null) {
1176 MethodType type = methodType(method.getReturnType(), method.getParameterTypes());
1177 MethodHandles.Lookup lookup = MethodHandles.lookup();
1178 Class<?> proxyInterface = findProxyInterfaceOrElseThrow(proxyClass, method);
1179 MethodHandle dmh;
1180 try {
1181 dmh = proxyClassLookup(lookup, proxyClass)
1182 .findSpecial(proxyInterface, method.getName(), type, proxyClass)
1183 .withVarargs(false);
1184 } catch (IllegalAccessException | NoSuchMethodException e) {
1185 // should not reach here
1186 throw new InternalError(e);
1187 }
1188 // this check can be turned into assertion as it is guaranteed to succeed by the virtue of
1189 // looking up a default (instance) method declared or inherited by proxyInterface
1190 // while proxyClass implements (is a subtype of) proxyInterface ...
1191 assert ((BooleanSupplier) () -> {
1192 try {
1193 // make sure that the method type matches
1194 dmh.asType(type.insertParameterTypes(0, proxyClass));
1195 return true;
1196 } catch (WrongMethodTypeException e) {
1197 return false;
1198 }
1199 }).getAsBoolean() : "Wrong method type";
1200 // change return type to Object
1201 MethodHandle mh = dmh.asType(dmh.type().changeReturnType(Object.class));
1202 // wrap any exception thrown with InvocationTargetException
1203 mh = MethodHandles.catchException(mh, Throwable.class, InvocationException.wrapMH());
1204 // spread array of arguments among parameters (skipping 1st parameter - target)
1205 mh = mh.asSpreader(1, Object[].class, type.parameterCount());
1206 // change target type to Object
1207 mh = mh.asType(MethodType.methodType(Object.class, Object.class, Object[].class));
1208
1209 // push MH into cache
1210 MethodHandle cached = methods.putIfAbsent(method, mh);
1211 if (cached != null) {
1212 superMH = cached;
1213 } else {
1214 superMH = mh;
1215 }
1216 }
1217 return superMH;
1218 }
1219
1220 /**
1221 * Finds the first proxy interface that declares the given method
1222 * directly or indirectly.
1223 *
1224 * @throws IllegalArgumentException if not found
1225 */
1226 private static Class<?> findProxyInterfaceOrElseThrow(Class<?> proxyClass, Method method) {
1227 Class<?> declaringClass = method.getDeclaringClass();
1228 if (!declaringClass.isInterface()) {
1229 throw new IllegalArgumentException("\"" + method +
1230 "\" is not a method declared in the proxy class");
1231 }
1232
1233 List<Class<?>> proxyInterfaces = Arrays.asList(proxyClass.getInterfaces());
1234 // the method's declaring class is a proxy interface
1235 if (proxyInterfaces.contains(declaringClass))
1236 return declaringClass;
1237
1238 // find the first proxy interface that inherits the default method
1239 // i.e. the declaring class of the default method is a superinterface
1240 // of the proxy interface
1241 Deque<Class<?>> deque = new ArrayDeque<>();
1242 Set<Class<?>> visited = new HashSet<>();
1243 boolean indirectMethodRef = false;
1244 for (Class<?> proxyIntf : proxyInterfaces) {
1245 assert proxyIntf != declaringClass;
1246 visited.add(proxyIntf);
1247 deque.add(proxyIntf);
1248
1249 // for each proxy interface, traverse its subinterfaces with
1250 // breadth-first search to find a subinterface declaring the
1251 // default method
1252 Class<?> c;
1253 while ((c = deque.poll()) != null) {
1254 if (c == declaringClass) {
1255 try {
1256 // check if this method is the resolved method if referenced from
1257 // this proxy interface (i.e. this method is not implemented
1258 // by any other superinterface)
1259 Method m = proxyIntf.getMethod(method.getName(), method.getSharedParameterTypes());
1260 if (m.getDeclaringClass() == declaringClass) {
1261 return proxyIntf;
1262 }
1263 indirectMethodRef = true;
1264 } catch (NoSuchMethodException e) {}
1265
1266 // skip traversing its superinterfaces
1267 // another proxy interface may extend it and so
1268 // the method's declaring class is left unvisited.
1269 continue;
1270 }
1271 // visit all superinteraces of one proxy interface to find if
1272 // this proxy interface inherits the method directly or indirectly
1273 visited.add(c);
1274 for (Class<?> superIntf : c.getInterfaces()) {
1275 if (!visited.contains(superIntf) && !deque.contains(superIntf)) {
1276 if (superIntf == declaringClass) {
1277 // fast-path as the matching subinterface is found
1278 deque.addFirst(superIntf);
1279 } else {
1280 deque.add(superIntf);
1281 }
1282 }
1283 }
1284 }
1285 }
1286
1287 throw new IllegalArgumentException("\"" + method + (indirectMethodRef
1288 ? "\" is overridden directly or indirectly by the proxy interfaces"
1289 : "\" is not a method declared in the proxy class"));
1290 }
1291
1292 /**
1293 * This method invokes the proxy's proxyClassLookup method to get a
1294 * Lookup on the proxy class.
1295 *
1296 * @return a lookup for proxy class of this proxy instance
1297 */
1298 @SuppressWarnings("removal")
1299 private static MethodHandles.Lookup proxyClassLookup(MethodHandles.Lookup caller, Class<?> proxyClass) {
1300 return AccessController.doPrivileged(new PrivilegedAction<>() {
1301 @Override
1302 public MethodHandles.Lookup run() {
1303 try {
1304 Method m = proxyClass.getDeclaredMethod("proxyClassLookup", MethodHandles.Lookup.class);
1305 m.setAccessible(true);
1306 return (MethodHandles.Lookup) m.invoke(null, caller);
1307 } catch (ReflectiveOperationException e) {
1308 throw new InternalError(e);
1309 }
1310 }
1311 });
1312 }
1313
1314 /*
1315 * Invoke the default method of the given proxy with an explicit caller class.
1316 *
1317 * @throws IllegalAccessException if the proxy interface is inaccessible to the caller
1318 * if caller is non-null
1319 */
1320 static Object invokeDefault(Object proxy, Method method, Object[] args, Class<?> caller)
1321 throws Throwable {
1322 // verify that the object is actually a proxy instance
1323 if (!Proxy.isProxyClass(proxy.getClass())) {
1324 throw new IllegalArgumentException("'proxy' is not a proxy instance");
1325 }
1326 if (!method.isDefault()) {
1327 throw new IllegalArgumentException("\"" + method + "\" is not a default method");
1328 }
1329 @SuppressWarnings("unchecked")
1330 Class<? extends Proxy> proxyClass = (Class<? extends Proxy>)proxy.getClass();
1331
1332 // skip access check if caller is null
1333 if (caller != null) {
1334 Class<?> intf = method.getDeclaringClass();
1335 // access check on the default method
1336 method.checkAccess(caller, intf, proxyClass, method.getModifiers());
1337 }
1338
1339 MethodHandle mh = Proxy.defaultMethodHandle(proxyClass, method);
1340 // invoke the super method
1341 try {
1342 // the args array can be null if the number of formal parameters required by
1343 // the method is zero (consistent with Method::invoke)
1344 Object[] params = args != null ? args : Proxy.EMPTY_ARGS;
1345 return mh.invokeExact(proxy, params);
1346 } catch (ClassCastException | NullPointerException e) {
1347 throw new IllegalArgumentException(e.getMessage(), e);
1348 } catch (Proxy.InvocationException e) {
1349 // unwrap and throw the exception thrown by the default method
1350 throw e.getCause();
1351 }
1352 }
1353
1354 /**
1355 * Internal exception type to wrap the exception thrown by the default method
1356 * so that it can distinguish CCE and NPE thrown due to the arguments
1357 * incompatible with the method signature.
1358 */
1359 static class InvocationException extends ReflectiveOperationException {
1360 @java.io.Serial
1361 private static final long serialVersionUID = 0L;
1362
1363 InvocationException(Throwable cause) {
1364 super(cause);
1365 }
1366
1367 /**
1368 * Wraps given cause with InvocationException and throws it.
1369 */
1370 static Object wrap(Throwable cause) throws InvocationException {
1371 throw new InvocationException(cause);
1372 }
1373
1374 @Stable
1375 static MethodHandle wrapMethodHandle;
1376
1377 static MethodHandle wrapMH() {
1378 MethodHandle mh = wrapMethodHandle;
1379 if (mh == null) {
1380 try {
1381 wrapMethodHandle = mh = MethodHandles.lookup().findStatic(
1382 InvocationException.class,
1383 "wrap",
1384 MethodType.methodType(Object.class, Throwable.class)
1385 );
1386 } catch (NoSuchMethodException | IllegalAccessException e) {
1387 throw new InternalError(e);
1388 }
1389 }
1390 return mh;
1391 }
1392 }
1393
1394 }