Before I start re-inventing the wheel, it might be better to ask the people on this list first: Has anybody already written a Haskell library for Java byte code manipulation (reading/writing class files, editing byte codes, etc.)? Something in the spirit of the Byte Code Engineering Library (http://jakarta.apache.org/bcel/) or the Jikes Bytecode Toolkit (http://www.alphaworks.ibm.com/tech/jikesbt/) would be extremely nice. It's not rocket science, but quite a bit of work. Given the ubiquity of Java I'd be surprised if no one has done this before... Cheers, S.