1 /* 2 * Copyright (c) 2013, 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 * @modules java.base/jdk.internal.misc 27 * @library /runtime/testlibrary /test/lib 28 * @library classes 29 * @build sun.hotspot.WhiteBox test.Empty 30 * @run main ClassFileInstaller sun.hotspot.WhiteBox 31 * sun.hotspot.WhiteBox$WhiteBoxPermission 32 * @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI UnloadTest 33 */ 34 import sun.hotspot.WhiteBox; 35 36 /** 37 * Test that verifies that classes are unloaded when they are no longer reachable. 38 * 39 * The test creates a class loader, uses the loader to load a class and creates an instance 40 * of that class. The it nulls out all the references to the instance, class and class loader 41 * and tries to trigger class unloading. Then it verifies that the class is no longer 42 * loaded by the VM. 43 */ 44 public class UnloadTest { 45 private static String className = "test.Empty"; 46 47 public static void main(String... args) throws Exception { 48 run(); 49 } 50 51 private static void run() throws Exception { 52 final WhiteBox wb = WhiteBox.getWhiteBox(); 53 54 ClassUnloadCommon.failIf(wb.isClassAlive(className), "is not expected to be alive yet"); 55 56 ClassLoader cl = ClassUnloadCommon.newClassLoader(); 57 Class<?> c = cl.loadClass(className); 58 Object o = c.newInstance(); 59 60 ClassUnloadCommon.failIf(!wb.isClassAlive(className), "should be live here"); 61 62 cl = null; c = null; o = null; 63 ClassUnloadCommon.triggerUnloading(); 64 ClassUnloadCommon.failIf(wb.isClassAlive(className), "should have been unloaded"); 65 } 66 } 67