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Javassist 3.15.0-GA, StackOverflowError with $sig in call to static method, can anyone confirm?
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created by <a href="http://community.jboss.org/people/wgayk">Wanja Gayk</a> in <i>Javassist</i> - <a href="http://community.jboss.org/message/643454#643454">View the full discussion</a>
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<div class="jive-rendered-content"><p>Cheers,</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>here's an Example of a possible bug I've found.</p><p>Could anyone confirm this or prove me an idiot, so I can either file a bug report or go kill myself in shame?</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Using $sig or $class as method parameter only seems to work on nonstatic methods, on static methods I get a StackOverflow Error.</p><p>Have I missed something in the dicumentation or is that a serious bug?</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I could reproduce this with the latest JRE6 and the current JRE7:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Using $sig:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>instrumenting class: de/plush/brix/instrumentation/Main (995 bytes)</p><p>instrumenting class: javassist/runtime/Desc (3280 bytes)</p><p>Exception in thread "main" java.lang.StackOverflowError</p><p> at javassist.runtime.Desc.getParams(Desc.java)</p><p> at javassist.runtime.Desc.getParams(Desc.java)</p><p> at javassist.runtime.Desc.getParams(Desc.java)</p><p>[..]</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Using $class:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>instrumenting class: de/plush/brix/instrumentation/Main (995 bytes)</p><p>instrumenting class: javassist/runtime/Desc (3280 bytes)</p><p>Exception in thread "main" java.lang.StackOverflowError</p><p> at javassist.runtime.Desc.getClazz(Desc.java)</p><p> at javassist.runtime.Desc.getClazz(Desc.java)</p><p>[...]</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Compile the following code, create JAR-File, have a manifest like:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Manifest-Version: 1.0</p><p>Ant-Version: Apache Ant 1.8.2</p><p>Created-By: 1.7.0_02-b13 (Oracle Corporation)</p><p>Premain-Class: de.plush.brix.instrumentation.Agent</p><p>Class-Path: javassist.jar</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Start some Main.class with the jvm-arg:</p><p>-javaagent:${project_loc}\Agent.jar</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>And watch it happen.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>package de.plush.brix.instrumentation;</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>public class Main {</p><p> void foo() {</p><p>  System.out.println("Hello world");</p><p>  }</p><p> public static void main(final String[] args) {</p><p>  new Main().foo();</p><p> }</p><p>}</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>package de.plush.brix.instrumentation;</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>import java.io.IOException;</p><p>import java.lang.instrument.ClassFileTransformer;</p><p>import java.lang.instrument.IllegalClassFormatException;</p><p>import java.lang.instrument.Instrumentation;</p><p>import java.lang.reflect.Modifier;</p><p>import java.security.ProtectionDomain;</p><p>import java.util.Arrays;</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>import javassist.ByteArrayClassPath;</p><p>import javassist.CannotCompileException;</p><p>import javassist.ClassPool;</p><p>import javassist.CtClass;</p><p>import javassist.CtMethod;</p><p>import javassist.NotFoundException;</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>public class Agent implements ClassFileTransformer {</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p> public Agent(final String agentArgs, final Instrumentation instrumentation) {</p><p>  instrumentation.addTransformer(this);</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p> public static void premain(final String agentArgs, final Instrumentation inst) {</p><p>  new Agent(agentArgs, inst);</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>public static void before(Class[] paramTypes) { //works</p><p> System.out.println("test passed");</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>public static void before(Class paramTypes) { //works</p><p> System.out.println("test passed");</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>public static void beforeStatic(Class[] paramTypes) { //stackOverflow</p><p>  System.out.println("test passed");</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>public static void beforeStatic2(Class paramTypes) { //stackOverflow</p><p> System.out.println("test passed");</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p> @Override</p><p> public byte[] transform(final ClassLoader loader, final String className, final Class<?> classBeingRedefined, final ProtectionDomain protectionDomain,</p><p> final byte[] classfileBuffer) throws IllegalClassFormatException {</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>  System.out.println("instrumenting class: " + className + " (" + classfileBuffer.length + " bytes)");</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>  try {</p><p>  final String javaClassName = className.replace('/', '.');</p><p>  // turn bytecodes into a Javassist CtClass</p><p>  final CtClass clazz = createClass(classfileBuffer, javaClassName);</p><p>  // add output at the beginning and end of each method</p><p>  for (final CtMethod method : clazz.getMethods()) {</p><p>   if (!isInherited(javaClassName, method)) {</p><p>     if (Modifier.isStatic(method.getModifiers())) {</p><p>      method.insertBefore("{"+Agent.class.getName() + ".beforeStatic($sig);}"); // -- $sig kills it!, also $class</p><p>      // method.insertBefore("{"+Agent.class.getName() + ".beforeStatic2($sig);}"); // -- kills it too!</p><p>     } else {</p><p>      method.insertBefore("{"+Agent.class.getName() + ".before($sig);}"); // -- $sig kills it!, also $class</p><p>      // method.insertBefore("{"+Agent.class.getName() + ".before2($class);}"); // -- kills it too!</p><p>    }</p><p>   }</p><p>  }</p><p>  return clazz.toBytecode();</p><p> } catch (final NotFoundException e) {</p><p>   throw new RuntimeException(e);</p><p> } catch (final CannotCompileException e) {</p><p>   if (!e.getMessage().contains("no method body")) {</p><p>    throw new RuntimeException(e);</p><p>   }</p><p>  // don't care</p><p> } catch (final IOException e) {</p><p>  throw new RuntimeException(e);</p><p> }</p><p> return classfileBuffer;</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>private boolean isInherited(final String javaClassName, final CtMethod method) {</p><p>  return !method.getLongName().startsWith(javaClassName);</p><p> }</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p> private CtClass createClass(final byte[] classfileBuffer, final String javassistClassName) throws NotFoundException {</p><p> final ClassPool cp = ClassPool.getDefault();</p><p> cp.insertClassPath(new ByteArrayClassPath(javassistClassName, classfileBuffer));</p><p> final CtClass cc = cp.get(javassistClassName);</p><p> return cc;</p><p> }</p><p>}</p></div>
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