1 /* 2 * Copyright (c) 2015, 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. 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 import sun.hotspot.WhiteBox; 26 27 public class HelloStringGC { 28 public static String[] array01 = new String[1000]; 29 public static String[] array02 = new String[1000]; 30 31 public static void main(String args[]) throws RuntimeException { 32 String testString1 = "shared_test_string_unique_14325"; 33 String testString2 = "test123"; 34 35 WhiteBox wb = WhiteBox.getWhiteBox(); 36 if (!wb.isShared(testString1) && !wb.areSharedStringsIgnored()) { 37 throw new RuntimeException("testString1 is not shared"); 38 } 39 40 for (int i=0; i<5; i++) { 41 allocSomeStrings(testString1, testString2); 42 array01 = null; 43 array02 = null; 44 System.gc(); 45 sleep(300); 46 array01 = new String[1000]; 47 array02 = new String[1000]; 48 } 49 50 wb.fullGC(); 51 52 System.out.println("HelloStringGC: PASS"); 53 } 54 55 private static void allocSomeStrings(String s1, String s2) { 56 for (int i = 0; i < 1000; i ++) { 57 array01[i] = new String(s1); 58 array02[i] = new String(s2); 59 } 60 } 61 62 private static void sleep(int ms) { 63 try { 64 Thread.sleep(ms); 65 } catch (InterruptedException e) { 66 } 67 } 68 69 }