Manipilacion de clases (Classloaders)

http://www.jboss.org/javassist

http://jakarta.apache.org/bcel/

http://cglib.sourceforge.net/

http://www.csg.is.titech.ac.jp/openjava/

http://www.java-opensource.com/open-source/aspect-oriented-frameworks.html

http://www.java-opensource.com/open-source/bytecode-libraries.html