Reading material

Chapter Threads: Doing Two or More Tasks At Once upto and including Understand Thread Priority of The Java Tutorial.

Additional material

Ken Arnold, James Gosling and David Holmes. The Java Programming Language. Third Edition. Addison-Wesley.
James Gosling, Bill Joy, Guy L. Steele Jr. and Gilad Bracha. The Java Language Specification. Second Edition. Addison-Wesley.
Doug Lea. Concurrent Programming in Java: Design Principles and Patterns. Second Edition. Addison-Wesley.

Thread
Runnable

Printer (using Thread)
PrinterTest
Printer (using Runnable)
Printer (using Runnable)
PrinterTest (using the third Printer class)
Runner
Race