Tutorial and Online Training from Sun Microsystems

http://java.sun.com/developer/onlineTraining/

Article on hyper threaded Java

http://www.javaworld.com/javaworld/jw-11-2006/jw-1121-thread.html

Thread Synchronization in Java

Detailed article on synchronization at thread level in Java : http://www.artima.com/insidejvm/ed2/threadsynch.html

Read chapter 17 in the spec from the inventors: http://java.sun.com/docs/books/jls/.