1 /* 2 * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.reflect; 27 28 import java.lang.invoke.MethodHandle; 29 import java.lang.invoke.MethodHandles; 30 import java.lang.invoke.MethodType; 31 import java.lang.invoke.WrongMethodTypeException; 32 import java.lang.module.ModuleDescriptor; 33 import java.security.AccessController; 34 import java.security.PrivilegedAction; 35 import java.util.ArrayDeque; 36 import java.util.Arrays; 37 import java.util.Collections; 38 import java.util.Deque; 39 import java.util.HashMap; 40 import java.util.HashSet; 41 import java.util.IdentityHashMap; 42 import java.util.List; 43 import java.util.Map; 44 import java.util.Objects; 45 import java.util.Set; 46 import java.util.concurrent.ConcurrentHashMap; 47 import java.util.concurrent.atomic.AtomicInteger; 48 import java.util.concurrent.atomic.AtomicLong; 49 import java.util.function.BooleanSupplier; 50 51 import jdk.internal.access.JavaLangAccess; 52 import jdk.internal.access.SharedSecrets; 53 import jdk.internal.value.PrimitiveClass; 54 import jdk.internal.module.Modules; 55 import jdk.internal.misc.VM; 56 import jdk.internal.reflect.CallerSensitive; 57 import jdk.internal.reflect.Reflection; 58 import jdk.internal.loader.ClassLoaderValue; 59 import jdk.internal.vm.annotation.Stable; 60 import sun.reflect.misc.ReflectUtil; 61 import sun.security.action.GetPropertyAction; 62 import sun.security.util.SecurityConstants; 63 64 import static java.lang.invoke.MethodType.methodType; 65 import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC; 66 67 /** 68 * 69 * {@code Proxy} provides static methods for creating objects that act like instances 70 * of interfaces but allow for customized method invocation. 71 * To create a proxy instance for some interface {@code Foo}: 72 * <pre>{@code 73 * InvocationHandler handler = new MyInvocationHandler(...); 74 * Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(), 75 * new Class<?>[] { Foo.class }, 76 * handler); 77 * }</pre> 78 * 79 * <p> 80 * A <em>proxy class</em> is a class created at runtime that implements a specified 81 * list of interfaces, known as <em>proxy interfaces</em>. A <em>proxy instance</em> 82 * is an instance of a proxy class. 83 * 84 * Each proxy instance has an associated <i>invocation handler</i> 85 * object, which implements the interface {@link InvocationHandler}. 86 * A method invocation on a proxy instance through one of its proxy 87 * interfaces will be dispatched to the {@link InvocationHandler#invoke 88 * invoke} method of the instance's invocation handler, passing the proxy 89 * instance, a {@code java.lang.reflect.Method} object identifying 90 * the method that was invoked, and an array of type {@code Object} 91 * containing the arguments. The invocation handler processes the 92 * encoded method invocation as appropriate and the result that it 93 * returns will be returned as the result of the method invocation on 94 * the proxy instance. 95 * 96 * <p>A proxy class has the following properties: 97 * 98 * <ul> 99 * <li>The unqualified name of a proxy class is unspecified. The space 100 * of class names that begin with the string {@code "$Proxy"} 101 * should be, however, reserved for proxy classes. 102 * 103 * <li>The package and module in which a proxy class is defined is specified 104 * <a href="#membership">below</a>. 105 * 106 * <li>A proxy class is <em>final and non-abstract</em>. 107 * 108 * <li>A proxy class extends {@code java.lang.reflect.Proxy}. 109 * 110 * <li>A proxy class implements exactly the interfaces specified at its 111 * creation, in the same order. Invoking {@link Class#getInterfaces() getInterfaces} 112 * on its {@code Class} object will return an array containing the same 113 * list of interfaces (in the order specified at its creation), invoking 114 * {@link Class#getMethods getMethods} on its {@code Class} object will return 115 * an array of {@code Method} objects that include all of the 116 * methods in those interfaces, and invoking {@code getMethod} will 117 * find methods in the proxy interfaces as would be expected. 118 * 119 * <li>The {@link java.security.ProtectionDomain} of a proxy class 120 * is the same as that of system classes loaded by the bootstrap class 121 * loader, such as {@code java.lang.Object}, because the code for a 122 * proxy class is generated by trusted system code. This protection 123 * domain will typically be granted {@code java.security.AllPermission}. 124 * 125 * <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method can be used 126 * to determine if a given class is a proxy class. 127 * </ul> 128 * 129 * <p>A proxy instance has the following properties: 130 * 131 * <ul> 132 * <li>Given a proxy instance {@code proxy} and one of the 133 * interfaces, {@code Foo}, implemented by its proxy class, the 134 * following expression will return true: 135 * <pre> 136 * {@code proxy instanceof Foo} 137 * </pre> 138 * and the following cast operation will succeed (rather than throwing 139 * a {@code ClassCastException}): 140 * <pre> 141 * {@code (Foo) proxy} 142 * </pre> 143 * 144 * <li>Each proxy instance has an associated invocation handler, the one 145 * that was passed to its constructor. The static 146 * {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method 147 * will return the invocation handler associated with the proxy instance 148 * passed as its argument. 149 * 150 * <li>An interface method invocation on a proxy instance will be 151 * encoded and dispatched to the invocation handler's {@link 152 * InvocationHandler#invoke invoke} method as described in the 153 * documentation for that method. 154 * 155 * <li>A proxy interface may define a default method or inherit 156 * a default method from its superinterface directly or indirectly. 157 * An invocation handler can invoke a default method of a proxy interface 158 * by calling {@link InvocationHandler#invokeDefault(Object, Method, Object...) 159 * InvocationHandler::invokeDefault}. 160 * 161 * <li>An invocation of the {@code hashCode}, 162 * {@code equals}, or {@code toString} methods declared in 163 * {@code java.lang.Object} on a proxy instance will be encoded and 164 * dispatched to the invocation handler's {@code invoke} method in 165 * the same manner as interface method invocations are encoded and 166 * dispatched, as described above. The declaring class of the 167 * {@code Method} object passed to {@code invoke} will be 168 * {@code java.lang.Object}. Other public methods of a proxy 169 * instance inherited from {@code java.lang.Object} are not 170 * overridden by a proxy class, so invocations of those methods behave 171 * like they do for instances of {@code java.lang.Object}. 172 * </ul> 173 * 174 * <h2><a id="membership">Package and Module Membership of Proxy Class</a></h2> 175 * 176 * The package and module to which a proxy class belongs are chosen such that 177 * the accessibility of the proxy class is in line with the accessibility of 178 * the proxy interfaces. Specifically, the package and the module membership 179 * of a proxy class defined via the 180 * {@link Proxy#getProxyClass(ClassLoader, Class[])} or 181 * {@link Proxy#newProxyInstance(ClassLoader, Class[], InvocationHandler)} 182 * methods is specified as follows: 183 * 184 * <ol> 185 * <li>If all the proxy interfaces are in <em>exported</em> or <em>open</em> 186 * packages: 187 * <ol type="a"> 188 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is 189 * <em>public</em> in an unconditionally exported but non-open package. 190 * The name of the package and the module are unspecified.</li> 191 * 192 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then 193 * the proxy class is <em>non-public</em> in the package and module of the 194 * non-public interfaces. All the non-public interfaces must be in the same 195 * package and module; otherwise, proxying them is 196 * <a href="#restrictions">not possible</a>.</li> 197 * </ol> 198 * </li> 199 * <li>If at least one proxy interface is in a package that is 200 * <em>non-exported</em> and <em>non-open</em>: 201 * <ol type="a"> 202 * <li>if all the proxy interfaces are <em>public</em>, then the proxy class is 203 * <em>public</em> in a <em>non-exported</em>, <em>non-open</em> package of 204 * <a href="#dynamicmodule"><em>dynamic module</em>.</a> 205 * The names of the package and the module are unspecified.</li> 206 * 207 * <li>if at least one of all the proxy interfaces is <em>non-public</em>, then 208 * the proxy class is <em>non-public</em> in the package and module of the 209 * non-public interfaces. All the non-public interfaces must be in the same 210 * package and module; otherwise, proxying them is 211 * <a href="#restrictions">not possible</a>.</li> 212 * </ol> 213 * </li> 214 * </ol> 215 * 216 * <p> 217 * Note that if proxy interfaces with a mix of accessibilities -- for example, 218 * an exported public interface and a non-exported non-public interface -- are 219 * proxied by the same instance, then the proxy class's accessibility is 220 * governed by the least accessible proxy interface. 221 * <p> 222 * Note that it is possible for arbitrary code to obtain access to a proxy class 223 * in an open package with {@link AccessibleObject#setAccessible setAccessible}, 224 * whereas a proxy class in a non-open package is never accessible to 225 * code outside the module of the proxy class. 226 * 227 * <p> 228 * Throughout this specification, a "non-exported package" refers to a package 229 * that is not exported to all modules, and a "non-open package" refers to 230 * a package that is not open to all modules. Specifically, these terms refer to 231 * a package that either is not exported/open by its containing module or is 232 * exported/open in a qualified fashion by its containing module. 233 * 234 * <h3><a id="dynamicmodule">Dynamic Modules</a></h3> 235 * <p> 236 * A dynamic module is a named module generated at runtime. A proxy class 237 * defined in a dynamic module is encapsulated and not accessible to any module. 238 * Calling {@link Constructor#newInstance(Object...)} on a proxy class in 239 * a dynamic module will throw {@code IllegalAccessException}; 240 * {@code Proxy.newProxyInstance} method should be used instead. 241 * 242 * <p> 243 * A dynamic module can read the modules of all of the superinterfaces of a proxy 244 * class and the modules of the classes and interfaces referenced by 245 * all public method signatures of a proxy class. If a superinterface or 246 * a referenced class or interface, say {@code T}, is in a non-exported package, 247 * the {@linkplain Module module} of {@code T} is updated to export the 248 * package of {@code T} to the dynamic module. 249 * 250 * <h3>Methods Duplicated in Multiple Proxy Interfaces</h3> 251 * 252 * <p>When two or more proxy interfaces contain a method with 253 * the same name and parameter signature, the order of the proxy class's 254 * interfaces becomes significant. When such a <i>duplicate method</i> 255 * is invoked on a proxy instance, the {@code Method} object passed 256 * to the invocation handler will not necessarily be the one whose 257 * declaring class is assignable from the reference type of the interface 258 * that the proxy's method was invoked through. This limitation exists 259 * because the corresponding method implementation in the generated proxy 260 * class cannot determine which interface it was invoked through. 261 * Therefore, when a duplicate method is invoked on a proxy instance, 262 * the {@code Method} object for the method in the foremost interface 263 * that contains the method (either directly or inherited through a 264 * superinterface) in the proxy class's list of interfaces is passed to 265 * the invocation handler's {@code invoke} method, regardless of the 266 * reference type through which the method invocation occurred. 267 * 268 * <p>If a proxy interface contains a method with the same name and 269 * parameter signature as the {@code hashCode}, {@code equals}, 270 * or {@code toString} methods of {@code java.lang.Object}, 271 * when such a method is invoked on a proxy instance, the 272 * {@code Method} object passed to the invocation handler will have 273 * {@code java.lang.Object} as its declaring class. In other words, 274 * the public, non-final methods of {@code java.lang.Object} 275 * logically precede all of the proxy interfaces for the determination of 276 * which {@code Method} object to pass to the invocation handler. 277 * 278 * <p>Note also that when a duplicate method is dispatched to an 279 * invocation handler, the {@code invoke} method may only throw 280 * checked exception types that are assignable to one of the exception 281 * types in the {@code throws} clause of the method in <i>all</i> of 282 * the proxy interfaces that it can be invoked through. If the 283 * {@code invoke} method throws a checked exception that is not 284 * assignable to any of the exception types declared by the method in one 285 * of the proxy interfaces that it can be invoked through, then an 286 * unchecked {@code UndeclaredThrowableException} will be thrown by 287 * the invocation on the proxy instance. This restriction means that not 288 * all of the exception types returned by invoking 289 * {@code getExceptionTypes} on the {@code Method} object 290 * passed to the {@code invoke} method can necessarily be thrown 291 * successfully by the {@code invoke} method. 292 * 293 * @author Peter Jones 294 * @see InvocationHandler 295 * @since 1.3 296 * @revised 9 297 */ 298 public class Proxy implements java.io.Serializable { 299 @java.io.Serial 300 private static final long serialVersionUID = -2222568056686623797L; 301 302 /** parameter types of a proxy class constructor */ 303 private static final Class<?>[] constructorParams = 304 { InvocationHandler.class }; 305 306 /** 307 * a cache of proxy constructors with 308 * {@link Constructor#setAccessible(boolean) accessible} flag already set 309 */ 310 private static final ClassLoaderValue<Constructor<?>> proxyCache = 311 new ClassLoaderValue<>(); 312 313 /** 314 * the invocation handler for this proxy instance. 315 * @serial 316 */ 317 @SuppressWarnings("serial") // Not statically typed as Serializable 318 protected InvocationHandler h; 319 320 /** 321 * Prohibits instantiation. 322 */ 323 private Proxy() { 324 } 325 326 /** 327 * Constructs a new {@code Proxy} instance from a subclass 328 * (typically, a dynamic proxy class) with the specified value 329 * for its invocation handler. 330 * 331 * @param h the invocation handler for this proxy instance 332 * 333 * @throws NullPointerException if the given invocation handler, {@code h}, 334 * is {@code null}. 335 */ 336 protected Proxy(InvocationHandler h) { 337 Objects.requireNonNull(h); 338 this.h = h; 339 } 340 341 /** 342 * Returns the {@code java.lang.Class} object for a proxy class 343 * given a class loader and an array of interfaces. The proxy class 344 * will be defined by the specified class loader and will implement 345 * all of the supplied interfaces. If any of the given interfaces 346 * is non-public, the proxy class will be non-public. If a proxy class 347 * for the same permutation of interfaces has already been defined by the 348 * class loader, then the existing proxy class will be returned; otherwise, 349 * a proxy class for those interfaces will be generated dynamically 350 * and defined by the class loader. 351 * 352 * @param loader the class loader to define the proxy class 353 * @param interfaces the list of interfaces for the proxy class 354 * to implement 355 * @return a proxy class that is defined in the specified class loader 356 * and that implements the specified interfaces 357 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 358 * restrictions</a> on the parameters are violated 359 * @throws SecurityException if a security manager, <em>s</em>, is present 360 * and any of the following conditions is met: 361 * <ul> 362 * <li> the given {@code loader} is {@code null} and 363 * the caller's class loader is not {@code null} and the 364 * invocation of {@link SecurityManager#checkPermission 365 * s.checkPermission} with 366 * {@code RuntimePermission("getClassLoader")} permission 367 * denies access.</li> 368 * <li> for each proxy interface, {@code intf}, 369 * the caller's class loader is not the same as or an 370 * ancestor of the class loader for {@code intf} and 371 * invocation of {@link SecurityManager#checkPackageAccess 372 * s.checkPackageAccess()} denies access to {@code intf}.</li> 373 * </ul> 374 * @throws NullPointerException if the {@code interfaces} array 375 * argument or any of its elements are {@code null} 376 * 377 * @deprecated Proxy classes generated in a named module are encapsulated 378 * and not accessible to code outside its module. 379 * {@link Constructor#newInstance(Object...) Constructor.newInstance} 380 * will throw {@code IllegalAccessException} when it is called on 381 * an inaccessible proxy class. 382 * Use {@link #newProxyInstance(ClassLoader, Class[], InvocationHandler)} 383 * to create a proxy instance instead. 384 * 385 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 386 * @revised 9 387 */ 388 @Deprecated 389 @CallerSensitive 390 public static Class<?> getProxyClass(ClassLoader loader, 391 Class<?>... interfaces) 392 throws IllegalArgumentException 393 { 394 @SuppressWarnings("removal") 395 Class<?> caller = System.getSecurityManager() == null 396 ? null 397 : Reflection.getCallerClass(); 398 399 return getProxyConstructor(caller, loader, interfaces) 400 .getDeclaringClass(); 401 } 402 403 /** 404 * Returns the {@code Constructor} object of a proxy class that takes a 405 * single argument of type {@link InvocationHandler}, given a class loader 406 * and an array of interfaces. The returned constructor will have the 407 * {@link Constructor#setAccessible(boolean) accessible} flag already set. 408 * 409 * @param caller passed from a public-facing @CallerSensitive method if 410 * SecurityManager is set or {@code null} if there's no 411 * SecurityManager 412 * @param loader the class loader to define the proxy class 413 * @param interfaces the list of interfaces for the proxy class 414 * to implement 415 * @return a Constructor of the proxy class taking single 416 * {@code InvocationHandler} parameter 417 */ 418 private static Constructor<?> getProxyConstructor(Class<?> caller, 419 ClassLoader loader, 420 Class<?>... interfaces) 421 { 422 // optimization for single interface 423 if (interfaces.length == 1) { 424 Class<?> intf = interfaces[0]; 425 if (caller != null) { 426 checkProxyAccess(caller, loader, intf); 427 } 428 return proxyCache.sub(intf).computeIfAbsent( 429 loader, 430 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build() 431 ); 432 } else { 433 // interfaces cloned 434 final Class<?>[] intfsArray = interfaces.clone(); 435 if (caller != null) { 436 checkProxyAccess(caller, loader, intfsArray); 437 } 438 final List<Class<?>> intfs = Arrays.asList(intfsArray); 439 return proxyCache.sub(intfs).computeIfAbsent( 440 loader, 441 (ld, clv) -> new ProxyBuilder(ld, clv.key()).build() 442 ); 443 } 444 } 445 446 /* 447 * Check permissions required to create a Proxy class. 448 * 449 * To define a proxy class, it performs the access checks as in 450 * Class.forName (VM will invoke ClassLoader.checkPackageAccess): 451 * 1. "getClassLoader" permission check if loader == null 452 * 2. checkPackageAccess on the interfaces it implements 453 * 454 * To get a constructor and new instance of a proxy class, it performs 455 * the package access check on the interfaces it implements 456 * as in Class.getConstructor. 457 * 458 * If an interface is non-public, the proxy class must be defined by 459 * the defining loader of the interface. If the caller's class loader 460 * is not the same as the defining loader of the interface, the VM 461 * will throw IllegalAccessError when the generated proxy class is 462 * being defined. 463 */ 464 private static void checkProxyAccess(Class<?> caller, 465 ClassLoader loader, 466 Class<?> ... interfaces) 467 { 468 @SuppressWarnings("removal") 469 SecurityManager sm = System.getSecurityManager(); 470 if (sm != null) { 471 ClassLoader ccl = caller.getClassLoader(); 472 if (loader == null && ccl != null) { 473 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); 474 } 475 ReflectUtil.checkProxyPackageAccess(ccl, interfaces); 476 } 477 } 478 479 /** 480 * Builder for a proxy class. 481 * 482 * If the module is not specified in this ProxyBuilder constructor, 483 * it will map from the given loader and interfaces to the module 484 * in which the proxy class will be defined. 485 */ 486 private static final class ProxyBuilder { 487 private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess(); 488 489 // prefix for all proxy class names 490 private static final String proxyClassNamePrefix = "$Proxy"; 491 492 // next number to use for generation of unique proxy class names 493 private static final AtomicLong nextUniqueNumber = new AtomicLong(); 494 495 // a reverse cache of defined proxy classes 496 private static final ClassLoaderValue<Boolean> reverseProxyCache = 497 new ClassLoaderValue<>(); 498 499 private record ProxyClassContext(Module module, String packageName, int accessFlags) { 500 private ProxyClassContext { 501 if (module.isNamed()) { 502 if (packageName.isEmpty()) { 503 // Per JLS 7.4.2, unnamed package can only exist in unnamed modules. 504 // This means a package-private superinterface exist in the unnamed 505 // package of a named module. 506 throw new InternalError("Unnamed package cannot be added to " + module); 507 } 508 509 if (!module.getDescriptor().packages().contains(packageName)) { 510 throw new InternalError(packageName + " not exist in " + module.getName()); 511 } 512 513 if (!module.isOpen(packageName, Proxy.class.getModule())) { 514 // Required for default method invocation 515 throw new InternalError(packageName + " not open to " + Proxy.class.getModule()); 516 } 517 } else { 518 if (Modifier.isPublic(accessFlags)) { 519 // All proxy superinterfaces are public, must be in named dynamic module 520 throw new InternalError("public proxy in unnamed module: " + module); 521 } 522 } 523 524 if ((accessFlags & ~(Modifier.PUBLIC | Modifier.IDENTITY)) != 0) { 525 throw new InternalError("proxy access flags must be Modifier.PUBLIC or 0"); 526 } 527 } 528 } 529 530 private static Class<?> defineProxyClass(ProxyClassContext context, List<Class<?>> interfaces) { 531 /* 532 * Choose a name for the proxy class to generate. 533 */ 534 long num = nextUniqueNumber.getAndIncrement(); 535 String proxyName = context.packageName().isEmpty() 536 ? proxyClassNamePrefix + num 537 : context.packageName() + "." + proxyClassNamePrefix + num; 538 539 ClassLoader loader = getLoader(context.module()); 540 trace(proxyName, context.module(), loader, interfaces); 541 542 /* 543 * Generate the specified proxy class. 544 */ 545 byte[] proxyClassFile = ProxyGenerator.generateProxyClass(loader, proxyName, interfaces, 546 context.accessFlags() | Modifier.FINAL | Modifier.IDENTITY); 547 try { 548 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile, 549 null, "__dynamic_proxy__"); 550 reverseProxyCache.sub(pc).putIfAbsent(loader, Boolean.TRUE); 551 return pc; 552 } catch (ClassFormatError e) { 553 /* 554 * A ClassFormatError here means that (barring bugs in the 555 * proxy class generation code) there was some other 556 * invalid aspect of the arguments supplied to the proxy 557 * class creation (such as virtual machine limitations 558 * exceeded). 559 */ 560 throw new IllegalArgumentException(e.toString()); 561 } 562 } 563 564 /** 565 * Test if given class is a class defined by 566 * {@link #defineProxyClass(ProxyClassContext, List)} 567 */ 568 static boolean isProxyClass(Class<?> c) { 569 return Objects.equals(reverseProxyCache.sub(c).get(c.getClassLoader()), 570 Boolean.TRUE); 571 } 572 573 private static boolean isExportedType(Class<?> c) { 574 String pn = c.getPackageName(); 575 return Modifier.isPublic(c.getModifiers()) && c.getModule().isExported(pn); 576 } 577 578 private static boolean isPackagePrivateType(Class<?> c) { 579 return !Modifier.isPublic(c.getModifiers()); 580 } 581 582 private static String toDetails(Class<?> c) { 583 String access = "unknown"; 584 if (isExportedType(c)) { 585 access = "exported"; 586 } else if (isPackagePrivateType(c)) { 587 access = "package-private"; 588 } else { 589 access = "module-private"; 590 } 591 ClassLoader ld = c.getClassLoader(); 592 return String.format(" %s/%s %s loader %s", 593 c.getModule().getName(), c.getName(), access, ld); 594 } 595 596 static void trace(String cn, 597 Module module, 598 ClassLoader loader, 599 List<Class<?>> interfaces) { 600 if (isDebug()) { 601 System.err.format("PROXY: %s/%s defined by %s%n", 602 module.getName(), cn, loader); 603 } 604 if (isDebug("debug")) { 605 interfaces.forEach(c -> System.out.println(toDetails(c))); 606 } 607 } 608 609 private static final String DEBUG = 610 GetPropertyAction.privilegedGetProperty("jdk.proxy.debug", ""); 611 612 private static boolean isDebug() { 613 return !DEBUG.isEmpty(); 614 } 615 private static boolean isDebug(String flag) { 616 return DEBUG.equals(flag); 617 } 618 619 // ProxyBuilder instance members start here.... 620 621 private final List<Class<?>> interfaces; 622 private final ProxyClassContext context; 623 ProxyBuilder(ClassLoader loader, List<Class<?>> interfaces) { 624 if (!VM.isModuleSystemInited()) { 625 throw new InternalError("Proxy is not supported until " 626 + "module system is fully initialized"); 627 } 628 if (interfaces.size() > 65535) { 629 throw new IllegalArgumentException("interface limit exceeded: " 630 + interfaces.size()); 631 } 632 633 Set<Class<?>> refTypes = referencedTypes(loader, interfaces); 634 635 // IAE if violates any restrictions specified in newProxyInstance 636 validateProxyInterfaces(loader, interfaces, refTypes); 637 638 this.interfaces = interfaces; 639 this.context = proxyClassContext(loader, interfaces, refTypes); 640 assert getLoader(context.module()) == loader; 641 } 642 643 ProxyBuilder(ClassLoader loader, Class<?> intf) { 644 this(loader, Collections.singletonList(intf)); 645 } 646 647 /** 648 * Generate a proxy class and return its proxy Constructor with 649 * accessible flag already set. If the target module does not have access 650 * to any interface types, IllegalAccessError will be thrown by the VM 651 * at defineClass time. 652 * 653 * Must call the checkProxyAccess method to perform permission checks 654 * before calling this. 655 */ 656 @SuppressWarnings("removal") 657 Constructor<?> build() { 658 Class<?> proxyClass = defineProxyClass(context, interfaces); 659 660 final Constructor<?> cons; 661 try { 662 cons = proxyClass.getConstructor(constructorParams); 663 } catch (NoSuchMethodException e) { 664 throw new InternalError(e.toString(), e); 665 } 666 AccessController.doPrivileged(new PrivilegedAction<Void>() { 667 public Void run() { 668 cons.setAccessible(true); 669 return null; 670 } 671 }); 672 return cons; 673 } 674 675 /** 676 * Validate the given proxy interfaces and the given referenced types 677 * are visible to the defining loader. 678 * 679 * @throws IllegalArgumentException if it violates the restrictions 680 * specified in {@link Proxy#newProxyInstance} 681 */ 682 private static void validateProxyInterfaces(ClassLoader loader, 683 List<Class<?>> interfaces, 684 Set<Class<?>> refTypes) 685 { 686 Map<Class<?>, Boolean> interfaceSet = new IdentityHashMap<>(interfaces.size()); 687 for (Class<?> intf : interfaces) { 688 /* 689 * Verify that the Class object actually represents an 690 * interface. 691 */ 692 if (!intf.isInterface()) { 693 throw new IllegalArgumentException(intf.getName() + " is not an interface"); 694 } 695 696 if (intf.isHidden()) { 697 throw new IllegalArgumentException(intf.getName() + " is a hidden interface"); 698 } 699 700 if (intf.isSealed()) { 701 throw new IllegalArgumentException(intf.getName() + " is a sealed interface"); 702 } 703 704 /* 705 * Verify that the class loader resolves the name of this 706 * interface to the same Class object. 707 */ 708 ensureVisible(loader, intf); 709 710 /* 711 * Verify that this interface is not a duplicate. 712 */ 713 if (interfaceSet.put(intf, Boolean.TRUE) != null) { 714 throw new IllegalArgumentException("repeated interface: " + intf.getName()); 715 } 716 } 717 718 for (Class<?> type : refTypes) { 719 ensureVisible(loader, type); 720 } 721 } 722 723 /* 724 * Returns all types referenced by all public non-static method signatures of 725 * the proxy interfaces 726 */ 727 private static Set<Class<?>> referencedTypes(ClassLoader loader, 728 List<Class<?>> interfaces) { 729 var types = new HashSet<Class<?>>(); 730 for (var intf : interfaces) { 731 for (Method m : intf.getMethods()) { 732 if (!Modifier.isStatic(m.getModifiers())) { 733 addElementType(types, m.getReturnType()); 734 addElementTypes(types, m.getSharedParameterTypes()); 735 addElementTypes(types, m.getSharedExceptionTypes()); 736 } 737 } 738 } 739 return types; 740 } 741 742 private static void addElementTypes(HashSet<Class<?>> types, 743 Class<?> ... classes) { 744 for (var cls : classes) { 745 addElementType(types, cls); 746 } 747 } 748 749 private static void addElementType(HashSet<Class<?>> types, 750 Class<?> cls) { 751 var type = getElementType(cls); 752 if (!type.isPrimitive()) { 753 types.add(type); 754 } 755 } 756 757 /** 758 * Returns the context for the generated proxy class, including the 759 * module and the package it belongs to and whether it is package-private. 760 * 761 * If any of proxy interface is package-private, then the proxy class 762 * is in the same package and module as the package-private interface. 763 * 764 * If all proxy interfaces are public and in exported packages, 765 * then the proxy class is in a dynamic module in an unconditionally 766 * exported package. 767 * 768 * If all proxy interfaces are public and at least one in a non-exported 769 * package, then the proxy class is in a dynamic module in a 770 * non-exported package. 771 * 772 * The package of proxy class is open to java.base for deep reflective access. 773 * 774 * Reads edge and qualified exports are added for dynamic module to access. 775 */ 776 private static ProxyClassContext proxyClassContext(ClassLoader loader, 777 List<Class<?>> interfaces, 778 Set<Class<?>> refTypes) { 779 Map<Class<?>, Module> packagePrivateTypes = new HashMap<>(); 780 boolean nonExported = false; 781 782 for (Class<?> intf : interfaces) { 783 Module m = intf.getModule(); 784 if (!Modifier.isPublic(intf.getModifiers())) { 785 packagePrivateTypes.put(intf, m); 786 } else { 787 if (!intf.getModule().isExported(intf.getPackageName())) { 788 // module-private types 789 nonExported = true; 790 } 791 } 792 } 793 794 if (packagePrivateTypes.size() > 0) { 795 // all package-private types must be in the same runtime package 796 // i.e. same package name and same module (named or unnamed) 797 // 798 // Configuration will fail if M1 and in M2 defined by the same loader 799 // and both have the same package p (so no need to check class loader) 800 Module targetModule = null; 801 String targetPackageName = null; 802 for (Map.Entry<Class<?>, Module> e : packagePrivateTypes.entrySet()) { 803 Class<?> intf = e.getKey(); 804 Module m = e.getValue(); 805 if ((targetModule != null && targetModule != m) || 806 (targetPackageName != null && targetPackageName != intf.getPackageName())) { 807 throw new IllegalArgumentException( 808 "cannot have non-public interfaces in different packages"); 809 } 810 if (getLoader(m) != loader) { 811 // the specified loader is not the same class loader 812 // of the non-public interface 813 throw new IllegalArgumentException( 814 "non-public interface is not defined by the given loader"); 815 } 816 817 targetModule = m; 818 targetPackageName = e.getKey().getPackageName(); 819 } 820 821 // validate if the target module can access all other interfaces 822 for (Class<?> intf : interfaces) { 823 Module m = intf.getModule(); 824 if (m == targetModule) continue; 825 826 if (!targetModule.canRead(m) || !m.isExported(intf.getPackageName(), targetModule)) { 827 throw new IllegalArgumentException(targetModule + " can't access " + intf.getName()); 828 } 829 } 830 831 // opens the package of the non-public proxy class for java.base to access 832 if (targetModule.isNamed()) { 833 Modules.addOpens(targetModule, targetPackageName, Proxy.class.getModule()); 834 } 835 // return the module of the package-private interface 836 return new ProxyClassContext(targetModule, targetPackageName, 0); 837 } 838 839 // All proxy interfaces are public. So maps to a dynamic proxy module 840 // and add reads edge and qualified exports, if necessary 841 Module targetModule = getDynamicModule(loader); 842 843 // set up proxy class access to proxy interfaces and types 844 // referenced in the method signature 845 Set<Class<?>> types = new HashSet<>(interfaces); 846 types.addAll(refTypes); 847 for (Class<?> c : types) { 848 ensureAccess(targetModule, c); 849 } 850 851 var pkgName = nonExported ? PROXY_PACKAGE_PREFIX + '.' + targetModule.getName() 852 : targetModule.getName(); 853 return new ProxyClassContext(targetModule, pkgName, Modifier.PUBLIC); 854 } 855 856 /* 857 * Ensure the given module can access the given class. 858 */ 859 private static void ensureAccess(Module target, Class<?> c) { 860 Module m = c.getModule(); 861 // add read edge and qualified export for the target module to access 862 if (!target.canRead(m)) { 863 Modules.addReads(target, m); 864 } 865 String pn = c.getPackageName(); 866 if (!m.isExported(pn, target)) { 867 Modules.addExports(m, pn, target); 868 } 869 } 870 871 /* 872 * Ensure the given class is visible to the class loader. 873 */ 874 private static void ensureVisible(ClassLoader ld, Class<?> c) { 875 Class<?> type = null; 876 try { 877 type = Class.forName(c.getName(), false, ld); 878 } catch (ClassNotFoundException e) { 879 } 880 if (PrimitiveClass.asPrimaryType(type) != PrimitiveClass.asPrimaryType(c)) { 881 throw new IllegalArgumentException(c.getName() + 882 " referenced from a method is not visible from class loader: " + JLA.getLoaderNameID(ld)); 883 } 884 } 885 886 private static Class<?> getElementType(Class<?> type) { 887 Class<?> e = type; 888 while (e.isArray()) { 889 e = e.getComponentType(); 890 } 891 return e; 892 } 893 894 private static final ClassLoaderValue<Module> dynProxyModules = 895 new ClassLoaderValue<>(); 896 private static final AtomicInteger counter = new AtomicInteger(); 897 898 /* 899 * Define a dynamic module with a package named $MODULE which 900 * is unconditionally exported and another package named 901 * com.sun.proxy.$MODULE which is encapsulated. 902 * 903 * Each class loader will have one dynamic module. 904 */ 905 private static Module getDynamicModule(ClassLoader loader) { 906 return dynProxyModules.computeIfAbsent(loader, (ld, clv) -> { 907 // create a dynamic module and setup module access 908 String mn = "jdk.proxy" + counter.incrementAndGet(); 909 String pn = PROXY_PACKAGE_PREFIX + "." + mn; 910 ModuleDescriptor descriptor = 911 ModuleDescriptor.newModule(mn, Set.of(SYNTHETIC)) 912 .packages(Set.of(pn, mn)) 913 .exports(mn) 914 .build(); 915 Module m = Modules.defineModule(ld, descriptor, null); 916 Modules.addReads(m, Proxy.class.getModule()); 917 Modules.addExports(m, mn); 918 // java.base to create proxy instance and access its Lookup instance 919 Modules.addOpens(m, pn, Proxy.class.getModule()); 920 Modules.addOpens(m, mn, Proxy.class.getModule()); 921 return m; 922 }); 923 } 924 } 925 926 /** 927 * Returns a proxy instance for the specified interfaces 928 * that dispatches method invocations to the specified invocation 929 * handler. 930 * <p> 931 * <a id="restrictions">{@code IllegalArgumentException} will be thrown 932 * if any of the following restrictions is violated:</a> 933 * <ul> 934 * <li>All of {@code Class} objects in the given {@code interfaces} array 935 * must represent {@linkplain Class#isHidden() non-hidden} and 936 * {@linkplain Class#isSealed() non-sealed} interfaces, 937 * not classes or primitive types. 938 * 939 * <li>No two elements in the {@code interfaces} array may 940 * refer to identical {@code Class} objects. 941 * 942 * <li>All of the interface types must be visible by name through the 943 * specified class loader. In other words, for class loader 944 * {@code cl} and every interface {@code i}, the following 945 * expression must be true:<p> 946 * {@code Class.forName(i.getName(), false, cl) == i} 947 * 948 * <li>All of the types referenced by all 949 * public method signatures of the specified interfaces 950 * and those inherited by their superinterfaces 951 * must be visible by name through the specified class loader. 952 * 953 * <li>All non-public interfaces must be in the same package 954 * and module, defined by the specified class loader and 955 * the module of the non-public interfaces can access all of 956 * the interface types; otherwise, it would not be possible for 957 * the proxy class to implement all of the interfaces, 958 * regardless of what package it is defined in. 959 * 960 * <li>For any set of member methods of the specified interfaces 961 * that have the same signature: 962 * <ul> 963 * <li>If the return type of any of the methods is a primitive 964 * type or void, then all of the methods must have that same 965 * return type. 966 * <li>Otherwise, one of the methods must have a return type that 967 * is assignable to all of the return types of the rest of the 968 * methods. 969 * </ul> 970 * 971 * <li>The resulting proxy class must not exceed any limits imposed 972 * on classes by the virtual machine. For example, the VM may limit 973 * the number of interfaces that a class may implement to 65535; in 974 * that case, the size of the {@code interfaces} array must not 975 * exceed 65535. 976 * </ul> 977 * 978 * <p>Note that the order of the specified proxy interfaces is 979 * significant: two requests for a proxy class with the same combination 980 * of interfaces but in a different order will result in two distinct 981 * proxy classes. 982 * 983 * @param loader the class loader to define the proxy class 984 * @param interfaces the list of interfaces for the proxy class 985 * to implement 986 * @param h the invocation handler to dispatch method invocations to 987 * @return a proxy instance with the specified invocation handler of a 988 * proxy class that is defined by the specified class loader 989 * and that implements the specified interfaces 990 * @throws IllegalArgumentException if any of the <a href="#restrictions"> 991 * restrictions</a> on the parameters are violated 992 * @throws SecurityException if a security manager, <em>s</em>, is present 993 * and any of the following conditions is met: 994 * <ul> 995 * <li> the given {@code loader} is {@code null} and 996 * the caller's class loader is not {@code null} and the 997 * invocation of {@link SecurityManager#checkPermission 998 * s.checkPermission} with 999 * {@code RuntimePermission("getClassLoader")} permission 1000 * denies access;</li> 1001 * <li> for each proxy interface, {@code intf}, 1002 * the caller's class loader is not the same as or an 1003 * ancestor of the class loader for {@code intf} and 1004 * invocation of {@link SecurityManager#checkPackageAccess 1005 * s.checkPackageAccess()} denies access to {@code intf};</li> 1006 * <li> any of the given proxy interfaces is non-public and the 1007 * caller class is not in the same {@linkplain Package runtime package} 1008 * as the non-public interface and the invocation of 1009 * {@link SecurityManager#checkPermission s.checkPermission} with 1010 * {@code ReflectPermission("newProxyInPackage.{package name}")} 1011 * permission denies access.</li> 1012 * </ul> 1013 * @throws NullPointerException if the {@code interfaces} array 1014 * argument or any of its elements are {@code null}, or 1015 * if the invocation handler, {@code h}, is 1016 * {@code null} 1017 * 1018 * @see <a href="#membership">Package and Module Membership of Proxy Class</a> 1019 * @revised 9 1020 */ 1021 @CallerSensitive 1022 public static Object newProxyInstance(ClassLoader loader, 1023 Class<?>[] interfaces, 1024 InvocationHandler h) { 1025 Objects.requireNonNull(h); 1026 1027 @SuppressWarnings("removal") 1028 final Class<?> caller = System.getSecurityManager() == null 1029 ? null 1030 : Reflection.getCallerClass(); 1031 1032 /* 1033 * Look up or generate the designated proxy class and its constructor. 1034 */ 1035 Constructor<?> cons = getProxyConstructor(caller, loader, interfaces); 1036 1037 return newProxyInstance(caller, cons, h); 1038 } 1039 1040 private static Object newProxyInstance(Class<?> caller, // null if no SecurityManager 1041 Constructor<?> cons, 1042 InvocationHandler h) { 1043 /* 1044 * Invoke its constructor with the designated invocation handler. 1045 */ 1046 try { 1047 if (caller != null) { 1048 checkNewProxyPermission(caller, cons.getDeclaringClass()); 1049 } 1050 1051 return cons.newInstance(new Object[]{h}); 1052 } catch (IllegalAccessException | InstantiationException e) { 1053 throw new InternalError(e.toString(), e); 1054 } catch (InvocationTargetException e) { 1055 Throwable t = e.getCause(); 1056 if (t instanceof RuntimeException re) { 1057 throw re; 1058 } else { 1059 throw new InternalError(t.toString(), t); 1060 } 1061 } 1062 } 1063 1064 private static void checkNewProxyPermission(Class<?> caller, Class<?> proxyClass) { 1065 @SuppressWarnings("removal") 1066 SecurityManager sm = System.getSecurityManager(); 1067 if (sm != null) { 1068 if (ReflectUtil.isNonPublicProxyClass(proxyClass)) { 1069 ClassLoader ccl = caller.getClassLoader(); 1070 ClassLoader pcl = proxyClass.getClassLoader(); 1071 1072 // do permission check if the caller is in a different runtime package 1073 // of the proxy class 1074 String pkg = proxyClass.getPackageName(); 1075 String callerPkg = caller.getPackageName(); 1076 1077 if (pcl != ccl || !pkg.equals(callerPkg)) { 1078 sm.checkPermission(new ReflectPermission("newProxyInPackage." + pkg)); 1079 } 1080 } 1081 } 1082 } 1083 1084 /** 1085 * Returns the class loader for the given module. 1086 */ 1087 @SuppressWarnings("removal") 1088 private static ClassLoader getLoader(Module m) { 1089 PrivilegedAction<ClassLoader> pa = m::getClassLoader; 1090 return AccessController.doPrivileged(pa); 1091 } 1092 1093 /** 1094 * Returns true if the given class is a proxy class. 1095 * 1096 * @implNote The reliability of this method is important for the ability 1097 * to use it to make security decisions, so its implementation should 1098 * not just test if the class in question extends {@code Proxy}. 1099 * 1100 * @param cl the class to test 1101 * @return {@code true} if the class is a proxy class and 1102 * {@code false} otherwise 1103 * @throws NullPointerException if {@code cl} is {@code null} 1104 * 1105 * @revised 9 1106 */ 1107 public static boolean isProxyClass(Class<?> cl) { 1108 return Proxy.class.isAssignableFrom(cl) && ProxyBuilder.isProxyClass(cl); 1109 } 1110 1111 /** 1112 * Returns the invocation handler for the specified proxy instance. 1113 * 1114 * @param proxy the proxy instance to return the invocation handler for 1115 * @return the invocation handler for the proxy instance 1116 * @throws IllegalArgumentException if the argument is not a 1117 * proxy instance 1118 * @throws SecurityException if a security manager, <em>s</em>, is present 1119 * and the caller's class loader is not the same as or an 1120 * ancestor of the class loader for the invocation handler 1121 * and invocation of {@link SecurityManager#checkPackageAccess 1122 * s.checkPackageAccess()} denies access to the invocation 1123 * handler's class. 1124 */ 1125 @SuppressWarnings("removal") 1126 @CallerSensitive 1127 public static InvocationHandler getInvocationHandler(Object proxy) 1128 throws IllegalArgumentException 1129 { 1130 /* 1131 * Verify that the object is actually a proxy instance. 1132 */ 1133 if (!isProxyClass(proxy.getClass())) { 1134 throw new IllegalArgumentException("not a proxy instance"); 1135 } 1136 1137 final Proxy p = (Proxy) proxy; 1138 final InvocationHandler ih = p.h; 1139 if (System.getSecurityManager() != null) { 1140 Class<?> ihClass = ih.getClass(); 1141 Class<?> caller = Reflection.getCallerClass(); 1142 if (ReflectUtil.needsPackageAccessCheck(caller.getClassLoader(), 1143 ihClass.getClassLoader())) 1144 { 1145 ReflectUtil.checkPackageAccess(ihClass); 1146 } 1147 } 1148 1149 return ih; 1150 } 1151 1152 private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE; 1153 1154 /** 1155 * A cache of Method -> MethodHandle for default methods. 1156 */ 1157 private static final ClassValue<ConcurrentHashMap<Method, MethodHandle>> 1158 DEFAULT_METHODS_MAP = new ClassValue<>() { 1159 @Override 1160 protected ConcurrentHashMap<Method, MethodHandle> computeValue(Class<?> type) { 1161 return new ConcurrentHashMap<>(4); 1162 } 1163 }; 1164 1165 private static ConcurrentHashMap<Method, MethodHandle> defaultMethodMap(Class<?> proxyClass) { 1166 assert isProxyClass(proxyClass); 1167 return DEFAULT_METHODS_MAP.get(proxyClass); 1168 } 1169 1170 static final Object[] EMPTY_ARGS = new Object[0]; 1171 1172 static MethodHandle defaultMethodHandle(Class<? extends Proxy> proxyClass, Method method) { 1173 // lookup the cached method handle 1174 ConcurrentHashMap<Method, MethodHandle> methods = defaultMethodMap(proxyClass); 1175 MethodHandle superMH = methods.get(method); 1176 if (superMH == null) { 1177 MethodType type = methodType(method.getReturnType(), method.getParameterTypes()); 1178 MethodHandles.Lookup lookup = MethodHandles.lookup(); 1179 Class<?> proxyInterface = findProxyInterfaceOrElseThrow(proxyClass, method); 1180 MethodHandle dmh; 1181 try { 1182 dmh = proxyClassLookup(lookup, proxyClass) 1183 .findSpecial(proxyInterface, method.getName(), type, proxyClass) 1184 .withVarargs(false); 1185 } catch (IllegalAccessException | NoSuchMethodException e) { 1186 // should not reach here 1187 throw new InternalError(e); 1188 } 1189 // this check can be turned into assertion as it is guaranteed to succeed by the virtue of 1190 // looking up a default (instance) method declared or inherited by proxyInterface 1191 // while proxyClass implements (is a subtype of) proxyInterface ... 1192 assert ((BooleanSupplier) () -> { 1193 try { 1194 // make sure that the method type matches 1195 dmh.asType(type.insertParameterTypes(0, proxyClass)); 1196 return true; 1197 } catch (WrongMethodTypeException e) { 1198 return false; 1199 } 1200 }).getAsBoolean() : "Wrong method type"; 1201 // change return type to Object 1202 MethodHandle mh = dmh.asType(dmh.type().changeReturnType(Object.class)); 1203 // wrap any exception thrown with InvocationTargetException 1204 mh = MethodHandles.catchException(mh, Throwable.class, InvocationException.wrapMH()); 1205 // spread array of arguments among parameters (skipping 1st parameter - target) 1206 mh = mh.asSpreader(1, Object[].class, type.parameterCount()); 1207 // change target type to Object 1208 mh = mh.asType(MethodType.methodType(Object.class, Object.class, Object[].class)); 1209 1210 // push MH into cache 1211 MethodHandle cached = methods.putIfAbsent(method, mh); 1212 if (cached != null) { 1213 superMH = cached; 1214 } else { 1215 superMH = mh; 1216 } 1217 } 1218 return superMH; 1219 } 1220 1221 /** 1222 * Finds the first proxy interface that declares the given method 1223 * directly or indirectly. 1224 * 1225 * @throws IllegalArgumentException if not found 1226 */ 1227 private static Class<?> findProxyInterfaceOrElseThrow(Class<?> proxyClass, Method method) { 1228 Class<?> declaringClass = method.getDeclaringClass(); 1229 if (!declaringClass.isInterface()) { 1230 throw new IllegalArgumentException("\"" + method + 1231 "\" is not a method declared in the proxy class"); 1232 } 1233 1234 List<Class<?>> proxyInterfaces = Arrays.asList(proxyClass.getInterfaces()); 1235 // the method's declaring class is a proxy interface 1236 if (proxyInterfaces.contains(declaringClass)) 1237 return declaringClass; 1238 1239 // find the first proxy interface that inherits the default method 1240 // i.e. the declaring class of the default method is a superinterface 1241 // of the proxy interface 1242 Deque<Class<?>> deque = new ArrayDeque<>(); 1243 Set<Class<?>> visited = new HashSet<>(); 1244 boolean indirectMethodRef = false; 1245 for (Class<?> proxyIntf : proxyInterfaces) { 1246 assert proxyIntf != declaringClass; 1247 visited.add(proxyIntf); 1248 deque.add(proxyIntf); 1249 1250 // for each proxy interface, traverse its subinterfaces with 1251 // breadth-first search to find a subinterface declaring the 1252 // default method 1253 Class<?> c; 1254 while ((c = deque.poll()) != null) { 1255 if (c == declaringClass) { 1256 try { 1257 // check if this method is the resolved method if referenced from 1258 // this proxy interface (i.e. this method is not implemented 1259 // by any other superinterface) 1260 Method m = proxyIntf.getMethod(method.getName(), method.getSharedParameterTypes()); 1261 if (m.getDeclaringClass() == declaringClass) { 1262 return proxyIntf; 1263 } 1264 indirectMethodRef = true; 1265 } catch (NoSuchMethodException e) {} 1266 1267 // skip traversing its superinterfaces 1268 // another proxy interface may extend it and so 1269 // the method's declaring class is left unvisited. 1270 continue; 1271 } 1272 // visit all superinterfaces of one proxy interface to find if 1273 // this proxy interface inherits the method directly or indirectly 1274 visited.add(c); 1275 for (Class<?> superIntf : c.getInterfaces()) { 1276 if (!visited.contains(superIntf) && !deque.contains(superIntf)) { 1277 if (superIntf == declaringClass) { 1278 // fast-path as the matching subinterface is found 1279 deque.addFirst(superIntf); 1280 } else { 1281 deque.add(superIntf); 1282 } 1283 } 1284 } 1285 } 1286 } 1287 1288 throw new IllegalArgumentException("\"" + method + (indirectMethodRef 1289 ? "\" is overridden directly or indirectly by the proxy interfaces" 1290 : "\" is not a method declared in the proxy class")); 1291 } 1292 1293 /** 1294 * This method invokes the proxy's proxyClassLookup method to get a 1295 * Lookup on the proxy class. 1296 * 1297 * @return a lookup for proxy class of this proxy instance 1298 */ 1299 @SuppressWarnings("removal") 1300 private static MethodHandles.Lookup proxyClassLookup(MethodHandles.Lookup caller, Class<?> proxyClass) { 1301 return AccessController.doPrivileged(new PrivilegedAction<>() { 1302 @Override 1303 public MethodHandles.Lookup run() { 1304 try { 1305 Method m = proxyClass.getDeclaredMethod("proxyClassLookup", MethodHandles.Lookup.class); 1306 m.setAccessible(true); 1307 return (MethodHandles.Lookup) m.invoke(null, caller); 1308 } catch (ReflectiveOperationException e) { 1309 throw new InternalError(e); 1310 } 1311 } 1312 }); 1313 } 1314 1315 /* 1316 * Invoke the default method of the given proxy with an explicit caller class. 1317 * 1318 * @throws IllegalAccessException if the proxy interface is inaccessible to the caller 1319 * if caller is non-null 1320 */ 1321 static Object invokeDefault(Object proxy, Method method, Object[] args, Class<?> caller) 1322 throws Throwable { 1323 // verify that the object is actually a proxy instance 1324 if (!Proxy.isProxyClass(proxy.getClass())) { 1325 throw new IllegalArgumentException("'proxy' is not a proxy instance"); 1326 } 1327 if (!method.isDefault()) { 1328 throw new IllegalArgumentException("\"" + method + "\" is not a default method"); 1329 } 1330 @SuppressWarnings("unchecked") 1331 Class<? extends Proxy> proxyClass = (Class<? extends Proxy>)proxy.getClass(); 1332 1333 // skip access check if caller is null 1334 if (caller != null) { 1335 Class<?> intf = method.getDeclaringClass(); 1336 // access check on the default method 1337 method.checkAccess(caller, intf, proxyClass, method.getModifiers()); 1338 } 1339 1340 MethodHandle mh = Proxy.defaultMethodHandle(proxyClass, method); 1341 // invoke the super method 1342 try { 1343 // the args array can be null if the number of formal parameters required by 1344 // the method is zero (consistent with Method::invoke) 1345 Object[] params = args != null ? args : Proxy.EMPTY_ARGS; 1346 return mh.invokeExact(proxy, params); 1347 } catch (ClassCastException | NullPointerException e) { 1348 throw new IllegalArgumentException(e.getMessage(), e); 1349 } catch (Proxy.InvocationException e) { 1350 // unwrap and throw the exception thrown by the default method 1351 throw e.getCause(); 1352 } 1353 } 1354 1355 /** 1356 * Internal exception type to wrap the exception thrown by the default method 1357 * so that it can distinguish CCE and NPE thrown due to the arguments 1358 * incompatible with the method signature. 1359 */ 1360 static class InvocationException extends ReflectiveOperationException { 1361 @java.io.Serial 1362 private static final long serialVersionUID = 0L; 1363 1364 InvocationException(Throwable cause) { 1365 super(cause); 1366 } 1367 1368 /** 1369 * Wraps given cause with InvocationException and throws it. 1370 */ 1371 static Object wrap(Throwable cause) throws InvocationException { 1372 throw new InvocationException(cause); 1373 } 1374 1375 @Stable 1376 static MethodHandle wrapMethodHandle; 1377 1378 static MethodHandle wrapMH() { 1379 MethodHandle mh = wrapMethodHandle; 1380 if (mh == null) { 1381 try { 1382 wrapMethodHandle = mh = MethodHandles.lookup().findStatic( 1383 InvocationException.class, 1384 "wrap", 1385 MethodType.methodType(Object.class, Throwable.class) 1386 ); 1387 } catch (NoSuchMethodException | IllegalAccessException e) { 1388 throw new InternalError(e); 1389 } 1390 } 1391 return mh; 1392 } 1393 } 1394 1395 }