Deadlock

http://javarevisited.blogspot.sg/2010/10/what-is-deadlock-in-java-how-to-fix-it.html

http://javapapers.com/core-java/java-jvm-memory-types/

http://javapapers.com/java/java-collections-interview-questions-part-i/#convert-list-to-set

http://www.drdobbs.com/web-development/restful-web-services-a-tutorial/240169069