1 /* 2 * Copyright (c) 2017, 2018, 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 java.lang.instrument.ClassFileTransformer; 26 import java.lang.instrument.Instrumentation; 27 import java.lang.instrument.IllegalClassFormatException; 28 import java.security.ProtectionDomain; 29 30 public class GCDuringDumpTransformer implements ClassFileTransformer { 31 public byte[] transform(ClassLoader loader, String name, Class<?> classBeingRedefined, 32 ProtectionDomain pd, byte[] buffer) throws IllegalClassFormatException { 33 try { 34 makeGarbage(); 35 } catch (Throwable t) { 36 t.printStackTrace(); 37 try { 38 Thread.sleep(200); // let GC to have a chance to run 39 } catch (Throwable t2) {} 40 } 41 42 return null; 43 } 44 45 private static Instrumentation savedInstrumentation; 46 47 public static void premain(String agentArguments, Instrumentation instrumentation) { 48 System.out.println("ClassFileTransformer.premain() is called"); 49 instrumentation.addTransformer(new GCDuringDumpTransformer(), /*canRetransform=*/true); 50 savedInstrumentation = instrumentation; 51 } 52 53 public static Instrumentation getInstrumentation() { 54 return savedInstrumentation; 55 } 56 57 public static void agentmain(String args, Instrumentation inst) throws Exception { 58 premain(args, inst); 59 } 60 61 public static void makeGarbage() { 62 for (int x=0; x<10; x++) { 63 Object[] a = new Object[10000]; 64 } 65 } 66 }