Create a thread-pool to execution concurrency - http://www.planetgeek.ch/2009/08/25/how-to-find-a-concurrency-bug-with-java/

http://legalizeadulthood.wordpress.com/2009/10/14/unit-testing-concurrency/

http://merereflections.wordpress.com/2010/01/20/unit-testing-multi-threaded-code-with-easymock/

Discussion about a tool that google used to test data racing - http://googletesting.blogspot.com.au/2014/06/threadsanitizer-slaughtering-data-races.html