ConcurrentHashMap: http://www.cnblogs.com/ITtangtang/p/3948786.html
HashMap: http://www.cnblogs.com/chenssy/p/3521565.html
TreeMap: http://blog.csdn.net/chenssy/article/details/26668941
HashMap: http://www.cnblogs.com/chenssy/p/3521565.html
LinkedHashMap: http://blog.csdn.net/u012889434/article/details/48055679
http://www.cnblogs.com/maowang1991/archive/2013/04/15/3023236.html
类加载机制: http://www.cnblogs.com/ityouknow/p/5603287.html
垃圾回收机制: http://www.cnblogs.com/andy-zcx/p/5522836.html