Packages 
Package Description
javassist
The Javassist Core API.
javassist.bytecode
Bytecode-level API.
javassist.bytecode.analysis
Bytecode Analysis API.
javassist.bytecode.annotation
Bytecode-level Annotations API.
javassist.compiler.ast  
javassist.expr
This package contains the classes for modifying a method body.
javassist.runtime
Runtime support classes required by modified bytecode.
javassist.tools
Covenient tools.
javassist.tools.reflect
Runtime Behavioral Reflection.
javassist.tools.rmi
Sample implementation of remote method invocation.
javassist.tools.web
Simple web server for running sample code.
javassist.util
Utility classes.
javassist.util.proxy
Dynamic proxy (similar to Enhancer of cglib).