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POjava.lang.reflect.InvocationTargetException gets thrown when bytecode instrumentation is finished with asm.
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  1. POjava.lang.reflect.InvocationTargetException gets thrown when bytecode instrumentation is finished with asm.
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    copied!<p>I wanted to instrument some methods/classes in Java. For that purpose I wrote an Java agent that instruments only a few classes that I choose. </p> <p>I use the following code to get the loaded classes and filter some of them:</p> <pre><code> instrumentation.addTransformer(myTransformer,true); Class[] loadedClasses=instrumentation.getAllLoadedClasses(); Class[] modifiableClasses=ModifiableClasses(loadedClasses,instrumentation); Class[] filteredClasses=filterClasses(modifiableClasses); if(instrumentation.isRetransformClassesSupported()){ System.out.println("retransformation is Supported"); instrumentation.retransformClasses(filteredClasses); } </code></pre> <p>this should not create any problem filterClasses returns some classes that I want to be instrumented normally I want to instrument these Classes:</p> <ul> <li>Ljava/nio/Buffer;</li> <li>Ljava/util/HashMap$Entry;</li> <li>Ljava/nio/HeapCharBuffer;</li> <li>Ljava/nio/CharBuffer;</li> <li>Ljava/lang/ClassLoader;</li> <li>Ljava/lang/Class;</li> <li>Ljava/util/HashMap;</li> <li>Ljava/nio/ByteBuffer;</li> <li>Ljava/lang/System;</li> <li>Ljava/io/BufferedWriter;</li> <li>Ljava/lang/String;</li> <li>Ljava/io/OutputStreamWriter;</li> <li>Ljava/io/BufferedOutputStream;</li> <li>Ljava/nio/charset/CoderResult;</li> <li>Ljava/io/Writer;</li> <li>Ljava/util/HashSet;</li> <li>Ljava/nio/charset/CharsetEncoder;</li> <li>Ljava/io/FileOutputStream;</li> <li>Ljava/io/PrintStream; </li> </ul> <p>everything works fine I print the instrumented and unistrumented classes in specific folders for debug. I use the asm CoreAPI to add some instructions at the beginning and the end of methods I dont instrument Constructors,native methods, abstract methods and static variables. When I just instrument the new classes that are being loaded everything works fine. I guess I dont understand something with the ClassLoader or something specific here is what I get on the Console: </p> <pre><code> Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at sun.instrument.InstrumentationImpl.loadClassAndStartAgent(Unknown Source) at sun.instrument.InstrumentationImpl.loadClassAndCallPremain(Unknown Source) Caused by: java.lang.InternalError at sun.instrument.InstrumentationImpl.retransformClasses0(Native Method) at sun.instrument.InstrumentationImpl.retransformClasses(Unknown Source) at my.Agent.Watcher.premain(Watcher.java:88) ... 6 more FATAL ERROR in native method: processing of -javaagent failed </code></pre> <p>I am thankful for any help I can get even a link or a hint in the right direction. </p>
 

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