BCEL: lighter than it looks
I mentioned BCEL earlier, but forgot to note the most wonderful thing I've learned about it. It's included in the JDK with Java 5.0. So, if you're working on some ultra-lightweight package and you want a small footprint for the purpose of embedding your software, have no fear.
BCEL is built in. Look in com.sun.org.apache.bcel.**.*
