BTrace links

http://blog.csdn.net/chaofanwei/article/details/20224339

http://learnworld.iteye.com/blog/1402763

http://jm-blog.aliapp.com/?p=322

http://java67.blogspot.hk/2012/09/top-10-java-design-pattern-interview-question-answer.html

http://blog.csdn.net/liyangbing315/article/details/5472862

http://java67.blogspot.sg/2012/09/top-10-java-design-pattern-interview-question-answer.html