1 /* 2 * Copyright (c) 2014, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test UnloadTest 26 * @library /runtime/testlibrary /testlibrary /testlibrary/whitebox 27 * @library classes 28 * @build ClassUnloadCommon test.Empty 29 * @build UnloadTest 30 * @run main/othervm/bootclasspath -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI UnloadTest 31 */ 32 import sun.hotspot.WhiteBox; 33 34 /** 35 * Test that verifies that classes are unloaded when they are no longer reachable. 36 * 37 * The test creates a class loader, uses the loader to load a class and creates an instance 38 * of that class. The it nulls out all the references to the instance, class and class loader 39 * and tries to trigger class unloading. Then it verifies that the class is no longer 40 * loaded by the VM. 41 */ 42 public class UnloadTest { 43 private static String className = "test.Empty"; 44 45 public static void main(String... args) throws Exception { 46 run(); 47 } 48 49 private static void run() throws Exception { 50 final WhiteBox wb = WhiteBox.getWhiteBox(); 51 52 ClassUnloadCommon.failIf(wb.isClassAlive(className), "is not expected to be alive yet"); 53 54 ClassLoader cl = ClassUnloadCommon.newClassLoader(); 55 Class<?> c = cl.loadClass(className); 56 Object o = c.newInstance(); 57 58 ClassUnloadCommon.failIf(!wb.isClassAlive(className), "should be live here"); 59 60 cl = null; c = null; o = null; 61 ClassUnloadCommon.triggerUnloading(); 62 ClassUnloadCommon.failIf(wb.isClassAlive(className), "should have been unloaded"); 63 } 64 } 65