Wow, it's great!
However, the section in the article
"Trust in the source, Luke?" is ...
hmm... it's true but I would like to say that
these problems are not specifications but
"not sufficiently well implemented features". :-p
Part 5 of the series (the second of three on Javassist) is finally out now, at http://www-106.ibm.com/developerworks/library/j-dyn0203.html This one covers classloading and load-time transformation. Part 6 should be out by the end of February, covering CodeConverter and ExprEditor usage.