Two weeks ago Sun Microsystems announced
opensourcing
href="http://openjdk.dev.java.net/">key Java implementations
including javac, the Java programming language compiler. You
can get the javac source code also from netbeans.org with a
detailedtutorial to
getting, building, and running the javac sources
in NetBeans IDE.
Since the javac sources are available as NetBeans project inside
the IDE, you can easily build and run the compiler as wellas investigate how things work...