Is there a java classfile / bytecode editor to edit instructions?

Question

Is there a utility (or eclipse plugin) for editing java class files? I'd like to manipulate the bytecode of a java class file without recompiling it nor having a complete buildpath.

E.g. to rename methods, add/delete instructions, change constants etc.

The only utilities I found are:

• classeditor but it's very limited in functionality (e.g. renaming of things and manipulating instructions isn't possible).

• jbe doesn't save changes (maybe because class verifying fails - before I made any changes, although the class runs perfectly)

  (jbe initially had a classpath issue, adding the class path to the jbe.bat file helped)

Answer 1

I have not seen any byte code -> byte code frontends, but plenty backends.

I would suggest that you have a look at the many byte code manipulation libraries like javassist which allow loading byte code, manipulate it, and save it back to disk, and then write a small main that does exactly that.

Answer 2

Find this list of byte code manipulation/code generation libraries helpful?