| /* |
| * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| import com.sun.management.DiagnosticCommandMBean; |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.InputStream; |
| import java.lang.instrument.ClassDefinition; |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.ThreadInfo; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.util.concurrent.CountDownLatch; |
| import javax.management.JMX; |
| import javax.management.ObjectName; |
| |
| /** |
| * When an exception is thrown, the JVM collects just enough information |
| * about the stack trace to be able to create a full fledged stack trace |
| * (StackTraceElement[]). The backtrace contains this information and the |
| * JVM must make sure that the data in the backtrace is still usable after |
| * a class redefinition. |
| * |
| * After the PermGen removal there was a bug when the last reference to a Method |
| * was in the backtrace. The class of the method was kept alive, because of the |
| * mirror stored in the backtrace, but the old versions of the redefined method |
| * could be freed, since class redefinition didn't know about the backtraces. |
| */ |
| public class RedefineMethodInBacktraceApp { |
| static boolean failed = false; |
| |
| public static void main(String args[]) throws Exception { |
| System.out.println("Hello from RedefineMethodInBacktraceApp!"); |
| new RedefineMethodInBacktraceApp().doTest(); |
| |
| if (failed) { |
| throw new Exception("ERROR: RedefineMethodInBacktraceApp failed."); |
| } |
| } |
| |
| public static CountDownLatch stop = new CountDownLatch(1); |
| public static CountDownLatch called = new CountDownLatch(1); |
| |
| private void doTest() throws Exception { |
| doMethodInBacktraceTest(); |
| doMethodInBacktraceTestB(); |
| } |
| |
| private void doMethodInBacktraceTest() throws Exception { |
| Throwable t1 = getThrowableFromMethodToRedefine(); |
| Throwable t2 = getThrowableFromMethodToDelete(); |
| |
| doRedefine(RedefineMethodInBacktraceTarget.class); |
| |
| doClassUnloading(); |
| |
| System.out.println("checking backtrace for throwable from methodToRedefine"); |
| touchRedefinedMethodInBacktrace(t1); |
| |
| System.out.println("checking backtrace for throwable from methodToDelete"); |
| touchRedefinedMethodInBacktrace(t2); |
| } |
| |
| private void doMethodInBacktraceTestB() throws Exception { |
| // Start a thread which blocks in method |
| Thread t = new Thread(RedefineMethodInBacktraceTargetB::methodToRedefine); |
| t.setDaemon(true); |
| t.start(); |
| |
| // Wait here until the new thread is in the method we want to redefine |
| called.await(); |
| |
| // Now redefine the class while the method is still on the stack of the new thread |
| doRedefine(RedefineMethodInBacktraceTargetB.class); |
| |
| // Do thread dumps in two different ways (to exercise different code paths) |
| // while the old class is still on the stack |
| |
| ThreadInfo[] tis = ManagementFactory.getThreadMXBean().dumpAllThreads(false, false); |
| for(ThreadInfo ti : tis) { |
| System.out.println(ti); |
| } |
| |
| String[] threadPrintArgs = {}; |
| Object[] dcmdArgs = {threadPrintArgs}; |
| String[] signature = {String[].class.getName()}; |
| System.out.println(ManagementFactory.getPlatformMBeanServer().invoke( |
| ObjectName.getInstance("com.sun.management:type=DiagnosticCommand"), |
| "threadPrint", |
| dcmdArgs, |
| signature)); |
| |
| // release the thread |
| stop.countDown(); |
| } |
| |
| private static Throwable getThrowableFromMethodToRedefine() throws Exception { |
| Class<RedefineMethodInBacktraceTarget> c = |
| RedefineMethodInBacktraceTarget.class; |
| Method method = c.getMethod("methodToRedefine"); |
| |
| Throwable thrownFromMethodToRedefine = null; |
| try { |
| method.invoke(null); |
| } catch (InvocationTargetException e) { |
| thrownFromMethodToRedefine = e.getCause(); |
| if (!(thrownFromMethodToRedefine instanceof RuntimeException)) { |
| throw e; |
| } |
| } catch (Exception e) { |
| e.printStackTrace(); |
| System.out.println("\nTest failed: unexpected exception: " + e.toString()); |
| failed = true; |
| } |
| method = null; |
| c = null; |
| |
| return thrownFromMethodToRedefine; |
| } |
| |
| private static Throwable getThrowableFromMethodToDelete() throws Exception { |
| Class<RedefineMethodInBacktraceTarget> c = |
| RedefineMethodInBacktraceTarget.class; |
| Method method = c.getMethod("callMethodToDelete"); |
| |
| Throwable thrownFromMethodToDelete = null; |
| try { |
| method.invoke(null); |
| } catch (InvocationTargetException e) { |
| thrownFromMethodToDelete = e.getCause(); |
| if (!(thrownFromMethodToDelete instanceof RuntimeException)) { |
| throw e; |
| } |
| } catch (Exception e) { |
| e.printStackTrace(); |
| System.out.println("\nTest failed: unexpected exception: " + e.toString()); |
| failed = true; |
| } |
| return thrownFromMethodToDelete; |
| } |
| |
| |
| private static void doClassUnloading() { |
| // This will clean out old, unused redefined methods. |
| System.gc(); |
| } |
| |
| private static void touchRedefinedMethodInBacktrace(Throwable throwable) { |
| throwable.printStackTrace(); |
| // Make sure that we can convert the backtrace, which is referring to |
| // the redefined method, to a StrackTraceElement[] without crashing. |
| StackTraceElement[] stackTrace = throwable.getStackTrace(); |
| for (int i = 0; i < stackTrace.length; i++) { |
| StackTraceElement frame = stackTrace[i]; |
| if (frame.getClassName() == null) { |
| System.out.println("\nTest failed: trace[" + i + "].getClassName() returned null"); |
| failed = true; |
| } |
| if (frame.getMethodName() == null) { |
| System.out.println("\nTest failed: trace[" + i + "].getMethodName() returned null"); |
| failed = true; |
| } |
| } |
| } |
| |
| private static void doRedefine(Class<?> clazz) throws Exception { |
| // Load the second version of this class. |
| File f = new File(clazz.getName() + ".class"); |
| System.out.println("Reading test class from " + f.getAbsolutePath()); |
| InputStream redefineStream = new FileInputStream(f); |
| |
| byte[] redefineBuffer = NamedBuffer.loadBufferFromStream(redefineStream); |
| |
| ClassDefinition redefineParamBlock = new ClassDefinition( |
| clazz, redefineBuffer); |
| |
| RedefineMethodInBacktraceAgent.getInstrumentation().redefineClasses( |
| new ClassDefinition[] {redefineParamBlock}); |
| } |
| } |