... as finally Eclipse java compiler is able to leverage
multicore machines to speed up compiles:
http://download.eclipse.org/eclipse/downloads/drops/S-3.4M7-200805020100/eclipse-news-M7.html
"You should see faster Java compile times when using machines with multiple CPUs. The Eclipse Compiler for Java (aka "ecj") is now taking advantage of the multi-threading capability of multi-CPU machines. The full build of a Java project also takes advantage of this support."
Good news 
Cheers
Andrea