java skill

http://www.open-open.com/doc/view/e989fe50b7a34fada189e62cfbee9045

Java class loader :

http://www.blogjava.net/lhulcn618/archive/2006/05/25/48230.html

Thread

http://www.javaworld.com/jw-04-1996/jw-04-threads.html?page=2

http://www.cnblogs.com/yshb/archive/2012/06/15/2550367.html

collection

http://tutorials.jenkov.com/java-collections/overview.html

《JAVA与模式》之访问者模式

http://www.cnblogs.com/java-my-life/archive/2012/06/14/2545381.html

jarFinder

http://www.jarfinder.com/index.php/java

http://www.blogjava.net/action/articles/17339.html

ClassLoader

http://www.javaworld.com/jw-10-1996/jw-10-indepth.html

http://blog.csdn.net/pengpenglin/article/details/1682858

SQL injection

http://www.cnblogs.com/kingboy2008/archive/2011/05/21/2052576.html

 java memory leak

http://www.ibm.com/developerworks/java/library/j-leaks/

http://olex.openlogic.com/wazi/2009/how-to-fix-memory-leaks-in-java/

Observer

http://www.cnblogs.com/wader2011/archive/2011/11/19/2254981.html