1 /* 2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang; 27 28 import java.lang.invoke.*; 29 import java.lang.invoke.MethodHandles.Lookup; 30 import java.lang.reflect.InvocationTargetException; 31 32 import static java.lang.invoke.MethodType.*; 33 34 /* 35 * Verify that a Lookup object can be obtained statically from java.base 36 * but fails when it's obtained via reflection from java.base. 37 */ 38 public class LookupTest { 39 public static void main(String... args) throws Throwable { 40 // Get a full power lookup 41 Lookup lookup1 = MethodHandles.lookup(); 42 MethodHandle mh1 = lookup1.findStatic(lookup1.lookupClass(), 43 "foo", 44 methodType(String.class)); 45 assertEquals((String) mh1.invokeExact(), foo()); 46 47 // access protected member 48 MethodHandle mh2 = lookup1.findVirtual(java.lang.ClassLoader.class, 49 "getPackage", 50 methodType(Package.class, String.class)); 51 ClassLoader loader = ClassLoader.getPlatformClassLoader(); 52 Package pkg = (Package)mh2.invokeExact(loader, "java.lang"); 53 assertEquals(pkg.getName(), "java.lang"); 54 55 // MethodHandles.lookup will fail if it's called reflectively 56 try { 57 MethodHandles.class.getMethod("lookup").invoke(null); 58 } catch (InvocationTargetException e) { 59 if (!(e.getCause() instanceof IllegalArgumentException)) { 60 throw e.getCause(); 61 } 62 } 63 } 64 65 static String foo() { return "foo!"; } 66 67 static void assertEquals(Object o1, Object o2) { 68 if (!o1.equals(o2)) { 69 throw new RuntimeException(o1 + " != " + o2); 70 } 71 } 72 }