1 /* 2 * Copyright (c) 2016, 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 package optionsvalidation; 25 26 import java.lang.ref.WeakReference; 27 28 class JVMStartup { 29 private static volatile WeakReference<Object> weakRef; 30 31 private static synchronized void createWeakRef() { 32 Object o = new Object(); 33 weakRef = new WeakReference<>(o); 34 } 35 36 /* Simple method to test that java start-up. Used for testing options. */ 37 public static void main(String[] args) throws Exception { 38 byte[] garbage = new byte[8192]; 39 int i = 0; 40 createWeakRef(); 41 do { 42 garbage = new byte[8192]; 43 i++; 44 /* Initiate GC after 5 iterations */ 45 if (i > 5) { 46 System.gc(); 47 } 48 } while(weakRef.get() != null); 49 System.out.println("Java start-up!"); 50 } 51 }