1 /* 2 * Copyright (c) 2014, 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 java.lang.instrument.ClassFileTransformer; 26 import java.lang.instrument.IllegalClassFormatException; 27 import java.security.ProtectionDomain; 28 29 // Note: Util is from /test/hotspot/jtreg/runtime/cds/test-classes/TestCommon.java 30 31 public class InstrumentationClassFileTransformer implements ClassFileTransformer { 32 public byte[] transform(ClassLoader loader, String name, Class<?> classBeingRedefined, 33 ProtectionDomain pd, byte[] buffer) throws IllegalClassFormatException { 34 35 if (name.startsWith("InstrumentationApp$") && !name.equals("InstrumentationApp$NotTransformed")) { 36 System.out.println("Transforming: " + name + " class = " + classBeingRedefined); 37 try { 38 if (classBeingRedefined == null) { 39 // Initial transform 40 replace(buffer, "buzz", "fuzz"); 41 } else { 42 replace(buffer, "buzz", "guzz"); // Retransform 43 replace(buffer, "huzz", "quzz"); // Redefine 44 } 45 } catch (Throwable t) { 46 t.printStackTrace(); 47 } 48 return buffer; 49 } 50 return null; 51 } 52 53 static void replace(byte[] buffer, String from, String to) { 54 int n = Util.replace(buffer, from, to); 55 System.out.println("..... replaced " + n + " occurrence(s) of '" + from + "' to '" + to + "'"); 56 } 57 }