I need tools to:
Since Java 6, the compiler has an API included in the JDK. Through it you can access the results of the Java parser through the
javax.lang.model APIs. The same functionality was present with JDK5 in the form of the Mirror API. There's a good introductory article here.
The best code generation tool I've seen is CodeModel. It has a very simple API and can generate multiple Java source files at once.