Threads - some resources on threads and concurrency

I'm currently studying threads for my Java 5 SCJP exam and have found this sample champter on Threads and Concurrency. Threads and concurrency are big subjects on the Java 5 SCJP exam so any extra help is welcome to me.

The book the exerct is from is called Java in a Nutshell, Fifth Edition

http://www.oreilly.com/catalog/javanut5/chapter/expt01.pdf

I have also found this introduction to threads from Java world

Probably the best resource on the subject and a good introduction is the threads tutorial on the sun site Lesson: Threads: Doing Two or More Tasks at Once it is quite detailed in explaining how to create threads and using them.