Java Bytecode Libraries

Why so many?

• BCEL
• ASM
• Serp
• Javassist
• Jas, by K. B. Sriram, is used by the Jasmin assembler, but seems otherwise extinct

See also another list.

Unverified things i've heard:

• BCEL hasn't been updated in ages
• ASM supports things BCEL doesn't, like annotations and generics, and is much faster because it's SAXy rather than DOMinant.
• "The BCEL project provides a JasminVisitor which will convert class files into jasmin assembly"
• The fastest out of ASM, BCEL, Serp, and Javassist is ASM.