I want to use
JRE's need to include the interfaces, and classes in that package, but do not need to provide implementations.
Sun's JRE doesn't, and returns null from calling
This other question addresses java 5.
Here's a blog post by Morten Nobel-Jørgensen on how to use eclipse's compiler as an implementation of javax.tools.JavaCompiler.
JavaCompiler javac = new EclipseCompiler();