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.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 */
296 public class Proxy implements java.io.Serializable {
297 @java.io.Serial
298 private static final long serialVersionUID = -2222568056686623797L;
299
300 /** parameter types of a proxy class constructor */
301 private static final Class<?>[] constructorParams =
302 { InvocationHandler.class };
303
304 /**
305 * a cache of proxy constructors with
306 * {@link Constructor#setAccessible(boolean) accessible} flag already set
307 */
308 private static final ClassLoaderValue<Constructor<?>> proxyCache =
309 new ClassLoaderValue<>();
310
311 /**
312 * the invocation handler for this proxy instance.
313 * @serial
314 */
315 @SuppressWarnings("serial") // Not statically typed as Serializable
316 protected InvocationHandler h;
317
318 /**
319 * Prohibits instantiation.
320 */
321 private Proxy() {
322 }
323
324 /**
325 * Constructs a new {@code Proxy} instance from a subclass
326 * (typically, a dynamic proxy class) with the specified value
327 * for its invocation handler.
328 *
329 * @param h the invocation handler for this proxy instance
330 *
331 * @throws NullPointerException if the given invocation handler, {@code h},
332 * is {@code null}.
333 */
334 protected Proxy(InvocationHandler h) {
335 Objects.requireNonNull(h);
336 this.h = h;
337 }
338
339 /**
340 * Returns the {@code java.lang.Class} object for a proxy class
341 * given a class loader and an array of interfaces. The proxy class
342 * will be defined by the specified class loader and will implement
343 * all of the supplied interfaces. If any of the given interfaces
344 * is non-public, the proxy class will be non-public. If a proxy class
345 * for the same permutation of interfaces has already been defined by the
346 * class loader, then the existing proxy class will be returned; otherwise,
347 * a proxy class for those interfaces will be generated dynamically
348 * and defined by the class loader.
349 *
350 * @param loader the class loader to define the proxy class
351 * @param interfaces the list of interfaces for the proxy class
352 * to implement
353 * @return a proxy class that is defined in the specified class loader
354 * and that implements the specified interfaces
355 * @throws IllegalArgumentException if any of the <a href="#restrictions">
356 * restrictions</a> on the parameters are violated
357 * @throws SecurityException if a security manager, <em>s</em>, is present
358 * and any of the following conditions is met:
359 * <ul>
360 * <li> the given {@code loader} is {@code null} and
361 * the caller's class loader is not {@code null} and the
362 * invocation of {@link SecurityManager#checkPermission
363 * s.checkPermission} with
364 * {@code RuntimePermission("getClassLoader")} permission
365 * denies access.</li>
366 * <li> for each proxy interface, {@code intf},
367 * the caller's class loader is not the same as or an
368 * ancestor of the class loader for {@code intf} and
369 * invocation of {@link SecurityManager#checkPackageAccess
370 * s.checkPackageAccess()} denies access to {@code intf}.</li>
371 * </ul>
372 * @throws NullPointerException if the {@code interfaces} array
373 * argument or any of its elements are {@code null}
374 *
375 * @deprecated Proxy classes generated in a named module are encapsulated
376 * and not accessible to code outside its module.
377 * {@link Constructor#newInstance(Object...) Constructor.newInstance}
378 * will throw {@code IllegalAccessException} when it is called on
379 * an inaccessible proxy class.
380 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)}
381 * to create a proxy instance instead.
382 *
383 * @see <a href="#membership">Package and Module Membership of Proxy Class</a>
384 */
385 @Deprecated
386 @CallerSensitive
387 public static Class<?> getProxyClass(ClassLoader loader,
388 Class<?>... interfaces)
389 throws IllegalArgumentException
390 {
391 @SuppressWarnings("removal")
392 Class<?> caller = System.getSecurityManager() == null
393 ? null
394 : Reflection.getCallerClass();
395
396 return getProxyConstructor(caller, loader, interfaces)
397 .getDeclaringClass();
398 }
399
400 /**
401 * Returns the {@code Constructor} object of a proxy class that takes a
402 * single argument of type {@link InvocationHandler}, given a class loader
403 * and an array of interfaces. The returned constructor will have the
404 * {@link Constructor#setAccessible(boolean) accessible} flag already set.
405 *
406 * @param caller passed from a public-facing @CallerSensitive method if
407 * SecurityManager is set or {@code null} if there's no
408 * SecurityManager
409 * @param loader the class loader to define the proxy class
410 * @param interfaces the list of interfaces for the proxy class
411 * to implement
412 * @return a Constructor of the proxy class taking single
413 * {@code InvocationHandler} parameter
414 */
415 private static Constructor<?> getProxyConstructor(Class<?> caller,
416 ClassLoader loader,
417 Class<?>... interfaces)
418 {
419 // optimization for single interface
420 if (interfaces.length == 1) {
421 Class<?> intf = interfaces[0];
422 if (caller != null) {
423 checkProxyAccess(caller, loader, intf);
424 }
425 return proxyCache.sub(intf).computeIfAbsent(
426 loader,
427 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
428 );
429 } else {
430 // interfaces cloned
431 final Class<?>[] intfsArray = interfaces.clone();
432 if (caller != null) {
433 checkProxyAccess(caller, loader, intfsArray);
434 }
435 final List<Class<?>> intfs = Arrays.asList(intfsArray);
436 return proxyCache.sub(intfs).computeIfAbsent(
437 loader,
438 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build()
439 );
440 }
441 }
442
443 /*
444 * Check permissions required to create a Proxy class.
445 *
446 * To define a proxy class, it performs the access checks as in
447 * Class.forName (VM will invoke ClassLoader.checkPackageAccess):
448 * 1. "getClassLoader" permission check if loader == null
449 * 2. checkPackageAccess on the interfaces it implements
450 *
451 * To get a constructor and new instance of a proxy class, it performs
452 * the package access check on the interfaces it implements
453 * as in Class.getConstructor.
454 *
455 * If an interface is non-public, the proxy class must be defined by
456 * the defining loader of the interface. If the caller's class loader
457 * is not the same as the defining loader of the interface, the VM
458 * will throw IllegalAccessError when the generated proxy class is
459 * being defined.
460 */
461 private static void checkProxyAccess(Class<?> caller,
462 ClassLoader loader,
463 Class<?> ... interfaces)
464 {
465 @SuppressWarnings("removal")
466 SecurityManager sm = System.getSecurityManager();
467 if (sm != null) {
468 ClassLoader ccl = caller.getClassLoader();
469 if (loader == null && ccl != null) {
470 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
471 }
472 ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
473 }
474 }
475
476 /**
477 * Builder for a proxy class.
478 *
479 * If the module is not specified in this ProxyBuilder constructor,
480 * it will map from the given loader and interfaces to the module
481 * in which the proxy class will be defined.
482 */
483 private static final class ProxyBuilder {
484 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
485
486 // prefix for all proxy class names
487 private static final String proxyClassNamePrefix = "$Proxy";
488
489 // next number to use for generation of unique proxy class names
490 private static final AtomicLong nextUniqueNumber = new AtomicLong();
491
492 // a reverse cache of defined proxy classes
493 private static final ClassLoaderValue<Boolean> reverseProxyCache =
494 new ClassLoaderValue<>();
495
496 private record ProxyClassContext(Module module, String packageName, int accessFlags) {
497 private ProxyClassContext {
498 if (module.isNamed()) {
499 if (packageName.isEmpty()) {
500 // Per JLS 7.4.2, unnamed package can only exist in unnamed modules.
501 // This means a package-private superinterface exist in the unnamed
502 // package of a named module.
503 throw new InternalError("Unnamed package cannot be added to " + module);
504 }
505
506 if (!module.getDescriptor().packages().contains(packageName)) {
507 throw new InternalError(packageName + " not exist in " + module.getName());
508 }
509
510 if (!module.isOpen(packageName, Proxy.class.getModule())) {
511 // Required for default method invocation
512 throw new InternalError(packageName + " not open to " + Proxy.class.getModule());
513 }
514 } else {
515 if (Modifier.isPublic(accessFlags)) {
516 // All proxy superinterfaces are public, must be in named dynamic module
517 throw new InternalError("public proxy in unnamed module: " + module);
518 }
519 }
520
521 if ((accessFlags & ~Modifier.PUBLIC) != 0) {
522 throw new InternalError("proxy access flags must be Modifier.PUBLIC or 0");
523 }
524 }
525 }
526
527 private static Class<?> defineProxyClass(ProxyClassContext context, List<Class<?>> interfaces) {
528 /*
529 * Choose a name for the proxy class to generate.
530 */
531 long num = nextUniqueNumber.getAndIncrement();
532 String proxyName = context.packageName().isEmpty()
533 ? proxyClassNamePrefix + num
534 : context.packageName() + "." + proxyClassNamePrefix + num;
535
536 ClassLoader loader = getLoader(context.module());
537 trace(proxyName, context.module(), loader, interfaces);
538
539 /*
540 * Generate the specified proxy class.
541 */
542 byte[] proxyClassFile = ProxyGenerator.generateProxyClass(loader, proxyName, interfaces,
543 context.accessFlags() | Modifier.FINAL);
544 try {
545 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
546 null, "__dynamic_proxy__");
547 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE);
548 return pc;
549 } catch (ClassFormatError e) {
550 /*
551 * A ClassFormatError here means that (barring bugs in the
552 * proxy class generation code) there was some other
553 * invalid aspect of the arguments supplied to the proxy
554 * class creation (such as virtual machine limitations
555 * exceeded).
556 */
557 throw new IllegalArgumentException(e.toString());
558 }
559 }
560
561 /**
562 * Test if given class is a class defined by
563 * {@link #defineProxyClass(ProxyClassContext, List)}
564 */
565 static boolean isProxyClass(Class<?> c) {
566 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()),
567 Boolean.TRUE);
568 }
569
570 private static boolean isExportedType(Class<?> c) {
571 String pn = c.getPackageName();
572 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn);
573 }
574
575 private static boolean isPackagePrivateType(Class<?> c) {
576 return !Modifier.isPublic(c.getModifiers());
577 }
578
579 private static String toDetails(Class<?> c) {
580 String access = "unknown";
581 if (isExportedType(c)) {
582 access = "exported";
583 } else if (isPackagePrivateType(c)) {
584 access = "package-private";
585 } else {
586 access = "module-private";
587 }
588 ClassLoader ld = c.getClassLoader();
589 return String.format(" %s/%s %s loader %s",
590 c.getModule().getName(), c.getName(), access, ld);
591 }
592
593 static void trace(String cn,
594 Module module,
595 ClassLoader loader,
596 List<Class<?>> interfaces) {
597 if (isDebug()) {
598 System.err.format("PROXY: %s/%s defined by %s%n",
599 module.getName(), cn, loader);
600 }
601 if (isDebug("debug")) {
602 interfaces.forEach(c -> System.out.println(toDetails(c)));
603 }
604 }
605
606 private static final String DEBUG =
607 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", "");
608
609 private static boolean isDebug() {
610 return !DEBUG.isEmpty();
611 }
612 private static boolean isDebug(String flag) {
613 return DEBUG.equals(flag);
614 }
615
616 // ProxyBuilder instance members start here....
617
618 private final List<Class<?>> interfaces;
619 private final ProxyClassContext context;
620 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) {
621 Objects.requireNonNull(interfaces);
622 if (!VM.isModuleSystemInited()) {
623 throw new InternalError("Proxy is not supported until "
624 + "module system is fully initialized");
625 }
626 if (interfaces.size() > 65535) {
627 throw new IllegalArgumentException("interface limit exceeded: "
628 + interfaces.size());
629 }
630
631 Set<Class<?>> refTypes = referencedTypes(loader, interfaces);
632
633 // IAE if violates any restrictions specified in newProxyInstance
634 validateProxyInterfaces(loader, interfaces, refTypes);
635
636 this.interfaces = interfaces;
637 this.context = proxyClassContext(loader, interfaces, refTypes);
638 assert getLoader(context.module()) == loader;
639 }
640
641 ProxyBuilder(ClassLoader loader, Class<?> intf) {
642 this(loader, Collections.singletonList(intf));
643 }
644
645 /**
646 * Generate a proxy class and return its proxy Constructor with
647 * accessible flag already set. If the target module does not have access
648 * to any interface types, IllegalAccessError will be thrown by the VM
649 * at defineClass time.
650 *
651 * Must call the checkProxyAccess method to perform permission checks
652 * before calling this.
653 */
654 @SuppressWarnings("removal")
655 Constructor<?> build() {
656 Class<?> proxyClass = defineProxyClass(context, interfaces);
657
658 final Constructor<?> cons;
659 try {
660 cons = proxyClass.getConstructor(constructorParams);
661 } catch (NoSuchMethodException e) {
662 throw new InternalError(e.toString(), e);
663 }
664 AccessController.doPrivileged(new PrivilegedAction<Void>() {
665 public Void run() {
666 cons.setAccessible(true);
667 return null;
668 }
669 });
670 return cons;
671 }
672
673 /**
674 * Validate the given proxy interfaces and the given referenced types
675 * are visible to the defining loader.
676 *
677 * @throws IllegalArgumentException if it violates the restrictions
678 * specified in {@link Proxy#newProxyInstance}
679 */
680 private static void validateProxyInterfaces(ClassLoader loader,
681 List<Class<?>> interfaces,
682 Set<Class<?>> refTypes)
683 {
684 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size());
685 for (Class<?> intf : interfaces) {
686 /*
687 * Verify that the Class object actually represents an
688 * interface.
689 */
690 if (!intf.isInterface()) {
691 throw new IllegalArgumentException(intf.getName() + " is not an interface");
692 }
693
694 if (intf.isHidden()) {
695 throw new IllegalArgumentException(intf.getName() + " is a hidden interface");
696 }
697
698 if (intf.isSealed()) {
699 throw new IllegalArgumentException(intf.getName() + " is a sealed interface");
700 }
701
702 /*
703 * Verify that the class loader resolves the name of this
704 * interface to the same Class object.
705 */
706 ensureVisible(loader, intf);
707
708 /*
709 * Verify that this interface is not a duplicate.
710 */
711 if (interfaceSet.put(intf, Boolean.TRUE) != null) {
712 throw new IllegalArgumentException("repeated interface: " + intf.getName());
713 }
714 }
715
716 for (Class<?> type : refTypes) {
717 ensureVisible(loader, type);
718 }
719 }
720
721 /*
722 * Returns all types referenced by all public non-static method signatures of
723 * the proxy interfaces
724 */
725 private static Set<Class<?>> referencedTypes(ClassLoader loader,
726 List<Class<?>> interfaces) {
727 var types = new HashSet<Class<?>>();
728 for (var intf : interfaces) {
729 for (Method m : intf.getMethods()) {
730 if (!Modifier.isStatic(m.getModifiers())) {
731 addElementType(types, m.getReturnType());
732 addElementTypes(types, m.getSharedParameterTypes());
733 addElementTypes(types, m.getSharedExceptionTypes());
734 }
735 }
736 }
737 return types;
738 }
739
740 private static void addElementTypes(HashSet<Class<?>> types,
741 Class<?> ... classes) {
742 for (var cls : classes) {
743 addElementType(types, cls);
744 }
745 }
746
747 private static void addElementType(HashSet<Class<?>> types,
748 Class<?> cls) {
749 var type = getElementType(cls);
750 if (!type.isPrimitive()) {
751 types.add(type);
752 }
753 }
754
755 /**
756 * Returns the context for the generated proxy class, including the
757 * module and the package it belongs to and whether it is package-private.
758 *
759 * If any of proxy interface is package-private, then the proxy class
760 * is in the same package and module as the package-private interface.
761 *
762 * If all proxy interfaces are public and in exported packages,
763 * then the proxy class is in a dynamic module in an unconditionally
764 * exported package.
765 *
766 * If all proxy interfaces are public and at least one in a non-exported
767 * package, then the proxy class is in a dynamic module in a
768 * non-exported package.
769 *
770 * The package of proxy class is open to java.base for deep reflective access.
771 *
772 * Reads edge and qualified exports are added for dynamic module to access.
773 */
774 private static ProxyClassContext proxyClassContext(ClassLoader loader,
775 List<Class<?>> interfaces,
776 Set<Class<?>> refTypes) {
777 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>();
778 boolean nonExported = false;
779
780 for (Class<?> intf : interfaces) {
781 Module m = intf.getModule();
782 if (!Modifier.isPublic(intf.getModifiers())) {
783 packagePrivateTypes.put(intf, m);
784 } else {
785 if (!intf.getModule().isExported(intf.getPackageName())) {
786 // module-private types
787 nonExported = true;
788 }
789 }
790 }
791
792 if (packagePrivateTypes.size() > 0) {
793 // all package-private types must be in the same runtime package
794 // i.e. same package name and same module (named or unnamed)
795 //
796 // Configuration will fail if M1 and in M2 defined by the same loader
797 // and both have the same package p (so no need to check class loader)
798 Module targetModule = null;
799 String targetPackageName = null;
800 for (Map.Entry<Class<?>, Module> e : packagePrivateTypes.entrySet()) {
801 Class<?> intf = e.getKey();
802 Module m = e.getValue();
803 if ((targetModule != null && targetModule != m) ||
804 (targetPackageName != null && targetPackageName != intf.getPackageName())) {
805 throw new IllegalArgumentException(
806 "cannot have non-public interfaces in different packages");
807 }
808 if (getLoader(m) != loader) {
809 // the specified loader is not the same class loader
810 // of the non-public interface
811 throw new IllegalArgumentException(
812 "non-public interface is not defined by the given loader");
813 }
814
815 targetModule = m;
816 targetPackageName = e.getKey().getPackageName();
817 }
818
819 // validate if the target module can access all other interfaces
820 for (Class<?> intf : interfaces) {
821 Module m = intf.getModule();
822 if (m == targetModule) continue;
823
824 if (!targetModule.canRead(m) || !m.isExported(intf.getPackageName(), targetModule)) {
825 throw new IllegalArgumentException(targetModule + " can't access " + intf.getName());
826 }
827 }
828
829 // opens the package of the non-public proxy class for java.base to access
830 if (targetModule.isNamed()) {
831 Modules.addOpens(targetModule, targetPackageName, Proxy.class.getModule());
832 }
833 // return the module of the package-private interface
834 return new ProxyClassContext(targetModule, targetPackageName, 0);
835 }
836
837 // All proxy interfaces are public. So maps to a dynamic proxy module
838 // and add reads edge and qualified exports, if necessary
839 Module targetModule = getDynamicModule(loader);
840
841 // set up proxy class access to proxy interfaces and types
842 // referenced in the method signature
843 Set<Class<?>> types = new HashSet<>(interfaces);
844 types.addAll(refTypes);
845 for (Class<?> c : types) {
846 ensureAccess(targetModule, c);
847 }
848
849 var pkgName = nonExported ? PROXY_PACKAGE_PREFIX + '.' + targetModule.getName()
850 : targetModule.getName();
851 return new ProxyClassContext(targetModule, pkgName, Modifier.PUBLIC);
852 }
853
854 /*
855 * Ensure the given module can access the given class.
856 */
857 private static void ensureAccess(Module target, Class<?> c) {
858 Module m = c.getModule();
859 if (target == m) return;
860
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 (type != 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 */
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 re) {
1056 throw re;
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 public static boolean isProxyClass(Class<?> cl) {
1105 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl);
1106 }
1107
1108 /**
1109 * Returns the invocation handler for the specified proxy instance.
1110 *
1111 * @param proxy the proxy instance to return the invocation handler for
1112 * @return the invocation handler for the proxy instance
1113 * @throws IllegalArgumentException if the argument is not a
1114 * proxy instance
1115 * @throws SecurityException if a security manager, <em>s</em>, is present
1116 * and the caller's class loader is not the same as or an
1117 * ancestor of the class loader for the invocation handler
1118 * and invocation of {@link SecurityManager#checkPackageAccess
1119 * s.checkPackageAccess()} denies access to the invocation
1120 * handler's class.
1121 */
1122 @SuppressWarnings("removal")
1123 @CallerSensitive
1124 public static InvocationHandler getInvocationHandler(Object proxy)
1125 throws IllegalArgumentException
1126 {
1127 /*
1128 * Verify that the object is actually a proxy instance.
1129 */
1130 if (!isProxyClass(proxy.getClass())) {
1131 throw new IllegalArgumentException("not a proxy instance");
1132 }
1133
1134 final Proxy p = (Proxy) proxy;
1135 final InvocationHandler ih = p.h;
1136 if (System.getSecurityManager() != null) {
1137 Class<?> ihClass = ih.getClass();
1138 Class<?> caller = Reflection.getCallerClass();
1139 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(),
1140 ihClass.getClassLoader()))
1141 {
1142 ReflectUtil.checkPackageAccess(ihClass);
1143 }
1144 }
1145
1146 return ih;
1147 }
1148
1149 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
1150
1151 /**
1152 * A cache of Method -> MethodHandle for default methods.
1153 */
1154 private static final ClassValue<ConcurrentHashMap<Method, MethodHandle>>
1155 DEFAULT_METHODS_MAP = new ClassValue<>() {
1156 @Override
1157 protected ConcurrentHashMap<Method, MethodHandle> computeValue(Class<?> type) {
1158 return new ConcurrentHashMap<>(4);
1159 }
1160 };
1161
1162 private static ConcurrentHashMap<Method, MethodHandle> defaultMethodMap(Class<?> proxyClass) {
1163 assert isProxyClass(proxyClass);
1164 return DEFAULT_METHODS_MAP.get(proxyClass);
1165 }
1166
1167 static final Object[] EMPTY_ARGS = new Object[0];
1168
1169 static MethodHandle defaultMethodHandle(Class<? extends Proxy> proxyClass, Method method) {
1170 // lookup the cached method handle
1171 ConcurrentHashMap<Method, MethodHandle> methods = defaultMethodMap(proxyClass);
1172 MethodHandle superMH = methods.get(method);
1173 if (superMH == null) {
1174 MethodType type = methodType(method.getReturnType(), method.getParameterTypes());
1175 MethodHandles.Lookup lookup = MethodHandles.lookup();
1176 Class<?> proxyInterface = findProxyInterfaceOrElseThrow(proxyClass, method);
1177 MethodHandle dmh;
1178 try {
1179 dmh = proxyClassLookup(lookup, proxyClass)
1180 .findSpecial(proxyInterface, method.getName(), type, proxyClass)
1181 .withVarargs(false);
1182 } catch (IllegalAccessException | NoSuchMethodException e) {
1183 // should not reach here
1184 throw new InternalError(e);
1185 }
1186 // this check can be turned into assertion as it is guaranteed to succeed by the virtue of
1187 // looking up a default (instance) method declared or inherited by proxyInterface
1188 // while proxyClass implements (is a subtype of) proxyInterface ...
1189 assert ((BooleanSupplier) () -> {
1190 try {
1191 // make sure that the method type matches
1192 dmh.asType(type.insertParameterTypes(0, proxyClass));
1193 return true;
1194 } catch (WrongMethodTypeException e) {
1195 return false;
1196 }
1197 }).getAsBoolean() : "Wrong method type";
1198 // change return type to Object
1199 MethodHandle mh = dmh.asType(dmh.type().changeReturnType(Object.class));
1200 // wrap any exception thrown with InvocationTargetException
1201 mh = MethodHandles.catchException(mh, Throwable.class, InvocationException.wrapMH());
1202 // spread array of arguments among parameters (skipping 1st parameter - target)
1203 mh = mh.asSpreader(1, Object[].class, type.parameterCount());
1204 // change target type to Object
1205 mh = mh.asType(MethodType.methodType(Object.class, Object.class, Object[].class));
1206
1207 // push MH into cache
1208 MethodHandle cached = methods.putIfAbsent(method, mh);
1209 if (cached != null) {
1210 superMH = cached;
1211 } else {
1212 superMH = mh;
1213 }
1214 }
1215 return superMH;
1216 }
1217
1218 /**
1219 * Finds the first proxy interface that declares the given method
1220 * directly or indirectly.
1221 *
1222 * @throws IllegalArgumentException if not found
1223 */
1224 private static Class<?> findProxyInterfaceOrElseThrow(Class<?> proxyClass, Method method) {
1225 Class<?> declaringClass = method.getDeclaringClass();
1226 if (!declaringClass.isInterface()) {
1227 throw new IllegalArgumentException("\"" + method +
1228 "\" is not a method declared in the proxy class");
1229 }
1230
1231 List<Class<?>> proxyInterfaces = Arrays.asList(proxyClass.getInterfaces());
1232 // the method's declaring class is a proxy interface
1233 if (proxyInterfaces.contains(declaringClass))
1234 return declaringClass;
1235
1236 // find the first proxy interface that inherits the default method
1237 // i.e. the declaring class of the default method is a superinterface
1238 // of the proxy interface
1239 Deque<Class<?>> deque = new ArrayDeque<>();
1240 Set<Class<?>> visited = new HashSet<>();
1241 boolean indirectMethodRef = false;
1242 for (Class<?> proxyIntf : proxyInterfaces) {
1243 assert proxyIntf != declaringClass;
1244 visited.add(proxyIntf);
1245 deque.add(proxyIntf);
1246
1247 // for each proxy interface, traverse its subinterfaces with
1248 // breadth-first search to find a subinterface declaring the
1249 // default method
1250 Class<?> c;
1251 while ((c = deque.poll()) != null) {
1252 if (c == declaringClass) {
1253 try {
1254 // check if this method is the resolved method if referenced from
1255 // this proxy interface (i.e. this method is not implemented
1256 // by any other superinterface)
1257 Method m = proxyIntf.getMethod(method.getName(), method.getSharedParameterTypes());
1258 if (m.getDeclaringClass() == declaringClass) {
1259 return proxyIntf;
1260 }
1261 indirectMethodRef = true;
1262 } catch (NoSuchMethodException e) {}
1263
1264 // skip traversing its superinterfaces
1265 // another proxy interface may extend it and so
1266 // the method's declaring class is left unvisited.
1267 continue;
1268 }
1269 // visit all superinterfaces of one proxy interface to find if
1270 // this proxy interface inherits the method directly or indirectly
1271 visited.add(c);
1272 for (Class<?> superIntf : c.getInterfaces()) {
1273 if (!visited.contains(superIntf) && !deque.contains(superIntf)) {
1274 if (superIntf == declaringClass) {
1275 // fast-path as the matching subinterface is found
1276 deque.addFirst(superIntf);
1277 } else {
1278 deque.add(superIntf);
1279 }
1280 }
1281 }
1282 }
1283 }
1284
1285 throw new IllegalArgumentException("\"" + method + (indirectMethodRef
1286 ? "\" is overridden directly or indirectly by the proxy interfaces"
1287 : "\" is not a method declared in the proxy class"));
1288 }
1289
1290 /**
1291 * This method invokes the proxy's proxyClassLookup method to get a
1292 * Lookup on the proxy class.
1293 *
1294 * @return a lookup for proxy class of this proxy instance
1295 */
1296 @SuppressWarnings("removal")
1297 private static MethodHandles.Lookup proxyClassLookup(MethodHandles.Lookup caller, Class<?> proxyClass) {
1298 return AccessController.doPrivileged(new PrivilegedAction<>() {
1299 @Override
1300 public MethodHandles.Lookup run() {
1301 try {
1302 Method m = proxyClass.getDeclaredMethod("proxyClassLookup", MethodHandles.Lookup.class);
1303 m.setAccessible(true);
1304 return (MethodHandles.Lookup) m.invoke(null, caller);
1305 } catch (ReflectiveOperationException e) {
1306 throw new InternalError(e);
1307 }
1308 }
1309 });
1310 }
1311
1312 /*
1313 * Invoke the default method of the given proxy with an explicit caller class.
1314 *
1315 * @throws IllegalAccessException if the proxy interface is inaccessible to the caller
1316 * if caller is non-null
1317 */
1318 static Object invokeDefault(Object proxy, Method method, Object[] args, Class<?> caller)
1319 throws Throwable {
1320 // verify that the object is actually a proxy instance
1321 if (!Proxy.isProxyClass(proxy.getClass())) {
1322 throw new IllegalArgumentException("'proxy' is not a proxy instance");
1323 }
1324 if (!method.isDefault()) {
1325 throw new IllegalArgumentException("\"" + method + "\" is not a default method");
1326 }
1327 @SuppressWarnings("unchecked")
1328 Class<? extends Proxy> proxyClass = (Class<? extends Proxy>)proxy.getClass();
1329
1330 // skip access check if caller is null
1331 if (caller != null) {
1332 Class<?> intf = method.getDeclaringClass();
1333 // access check on the default method
1334 method.checkAccess(caller, intf, proxyClass, method.getModifiers());
1335 }
1336
1337 MethodHandle mh = Proxy.defaultMethodHandle(proxyClass, method);
1338 // invoke the super method
1339 try {
1340 // the args array can be null if the number of formal parameters required by
1341 // the method is zero (consistent with Method::invoke)
1342 Object[] params = args != null ? args : Proxy.EMPTY_ARGS;
1343 return mh.invokeExact(proxy, params);
1344 } catch (ClassCastException | NullPointerException e) {
1345 throw new IllegalArgumentException(e.getMessage(), e);
1346 } catch (Proxy.InvocationException e) {
1347 // unwrap and throw the exception thrown by the default method
1348 throw e.getCause();
1349 }
1350 }
1351
1352 /**
1353 * Internal exception type to wrap the exception thrown by the default method
1354 * so that it can distinguish CCE and NPE thrown due to the arguments
1355 * incompatible with the method signature.
1356 */
1357 static class InvocationException extends ReflectiveOperationException {
1358 @java.io.Serial
1359 private static final long serialVersionUID = 0L;
1360
1361 InvocationException(Throwable cause) {
1362 super(cause);
1363 }
1364
1365 /**
1366 * Wraps given cause with InvocationException and throws it.
1367 */
1368 static Object wrap(Throwable cause) throws InvocationException {
1369 throw new InvocationException(cause);
1370 }
1371
1372 @Stable
1373 static MethodHandle wrapMethodHandle;
1374
1375 static MethodHandle wrapMH() {
1376 MethodHandle mh = wrapMethodHandle;
1377 if (mh == null) {
1378 try {
1379 wrapMethodHandle = mh = MethodHandles.lookup().findStatic(
1380 InvocationException.class,
1381 "wrap",
1382 MethodType.methodType(Object.class, Throwable.class)
1383 );
1384 } catch (NoSuchMethodException | IllegalAccessException e) {
1385 throw new InternalError(e);
1386 }
1387 }
1388 return mh;
1389 }
1390 }
1391
1392 }