Recompile decompiled Java (JD / JAD) source that contains goto instructions

Question

(Related question: Java compilers or JVM languages that support goto?)

I have decompiled a jar (Legally, for debugging purposes) and want to recompile it.

I've used both JAD and JD and both don't compile due to goto instructions

E.g.

      goto _L1

      ...
      L1: 
      return true;

Is there an easy way (or any way) to recompile it? (Except to manually refactor and remove the goto's)

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Answer 1

No, there isn't. In your case, neither JD nor JAD were able to decompile the class files correctly. The 'goto' statements are a hint about the actual program flow.

You could contact the Java Decompiler team directly, send in a class file where decompilation results in illegal source code and ask if it's a bug in the current version or a feature that has not yet been implemented.

Answer 2

JAD is a really amazing decompiler, JD ... have some problems with the "try-catch-finally" statements.

Have you try the decompiler of Stiver (http://www.reversed-java.com/fernflower) ?

Emmanuel, author of JD.

Answer 3

All decompilers look for code patterns corresponding to Java source constructions and choose the source that fits the best.

Apparently the code you have does not conform to any pattern stored in either JAD or JD so you get uncompilable Java source. This is most likely because JAD has not been actively developed for several years.

I would suggest you look at the Soot project which has a much more aggressive decompiler.

http://www.sable.mcgill.ca/soot/