bytecode-manipulation

Enviroment I am using a third party lib which requires bytecode instrumentation. The tool which does the bytecode instrumentation requires some description files and those files have to be in the same folder structure like the compiled .class files. Those files are only necessary at compiletime. Problem I thought gradle would place all files (resource and class) temporarily within the same folder and then create a jar from that folder. But it seems that gradle have two different places for resources and class files before assembling a jar. Like mentioned before the third party tool for code

Disassembling some Java 8 code I found out that some invokestatic calls on static methods in interface (particularly this was java.util.function.Function.identity() ) uses InterfaceMethodRef in const pool; this is what javap -s -c -v p show me: 15: invokestatic #66 // InterfaceMethod java/util/function/Function.identity:()Ljava/util/function/Function; According to JVM 8 spec this is not possible, and when I've used this instruction in classfile with version Java 7 ( major version=51 ), it has thrown VerifyError on this instruction. However, when I've changed the major version to 52 , it

Someone where i work noticed (in stacktrace) that when running the jvm with -javaagent:spring-instrumentation.jar my JAXB annotated classes have strange new methods in them which we didn't write: e.g. SomeJaxbAnnotatedClass$JaxbAccessorM_getFields_setFields_java_util_Set.get Does this mean that jaxb uses bytecode instrumentation when it is available? Where can i read more about this functionality? Thanks, Yuval Just an addition to skaffman's post: What you see (SomeJaxbAnnotatedClass$JaxbAccessor...) is an inner class, which is generated dynamically by the JAXB reference implementation. To

Closed . This question needs to be more focused . It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post . Closed 3 years ago . I recently came across the term "Bytecode manipulation" (what made to look into this, by chance I saw bytecode provider while seeing the logs in an application which used Hibernate) . I also know (a bit) about Java Reflection API. Are these two concepts similar? What are the difference between them? When to use which? Reflection API allows you to access the information about the

Our project does some Java bytecode instrumentation. And we stumbled upon some strange behavior. Suppose the following code snippet: public void a() { new Integer(2); } Oracle's javac compiles the above into the following bytecode: 0: new #2; //class java/lang/Integer 3: dup 4: iconst_2 5: invokespecial #3; //Method java/lang/Integer."<init>":(I)V 8: pop 9: return and Eclipse's compiler into: 0: new #15; //class java/lang/Integer 3: iconst_2 4: invokespecial #17; //Method java/lang/Integer."<init>":(I)V 7: return As you can see, Oracle compiler produces "dup" after "new", whereas Eclipse doesn

Motivation I have a SomeObject.java file: class SomeObject { String name; } Compiling it creates a bytecode-containing SomeObject.class file. 0xCAFEBABE... If we use SomeObject on the JVM, it is loaded by the current classloader and all works fine. Now let's assume that I'd like to have some dynamic code generation. I can write my custom annotation @Target(ElementType.TYPE) public @interface Data { ... } and add it as a modifier to the class declaration: @Data class SomeObject { String name; } I can also retain it for the runtime with @Retention(RetentionPolicy.RUNTIME) : @Retention

for bytecode instrumentation in java, there is the asm framework and the bcel and javaassist libraries. However I need to do instrumentation in native code, since some java classes are already loaded by the time the javaagent runs, eg java.lang.Thread, java.lang.Class, etc is there any library for instrumenting java classes in native code? Edit: Seems there is a bit of confusion. What I want is: Create a native java agent, which uses JVMTI apis to change the bytecode of a class while its being loaded, using the OnClassLoad event hook. I encountered this problem during my doctoral research. The