1. Spring framework J2EE framework http://www.springframework.org/
2. Struts Web framework http://struts.apache.org/
3. hibernate persistent http://www.hibernate.org/
4. webwork Web framework http://www.opensymphony.com/webwork/
5. Velocity template engine http://jakarta.apache.org/velocity/.
6. ibatis permanent http://ibatis.apache.org/
7. Eclipse open-source ide http://www.eclipse.org/
8. tapestry Web framework http://jakarta.apache.org/tapestry/
9. Lucene text search http://jakarta.apache.org/lucene/docs/index.html
10. itext PDF Processing http://www.lowagie.com/iText/
11. JUnit unit testing Co., http://www.junit.org/
12. Compiere ERP & CRM open source ERP http://www.compiere.org/
13. xplanner XP project management http://www.xplanner.org/
14. roroller weblogger open source blog http://www.rollerweblogger.org/
15. JBoss open source server Co., http://www.jboss.org/
16. glassfish open source server Co., https://glassfish.dev.java.net/
17. jbpm Open Source Workflow http://www.jbpm.org/
18. osworkflow open source flow http://www.opensymphony.com/osworkflow/
19. jforum BBS system http://www.jforum.net/index.jsp
20. hypersonic SQL Java RDS http://hsqldb.sourceforge.net/
21. Oscache cache system http://www.opensymphony.com/oscache/
22. jasperreports report tool http://jasperreports.sourceforge.net/
23. ireport report design tools http://ireport.sourceforge.net/
24. Eclipse Birt report system http://www.eclipse.org/birt/
Www.sourceforge.net
Www.gnu.org
Www.kernel.org
Http://oss.lupaworld.com/
Http://code.google.com/intl/zh-CN/
Http://www.oschina.net/
Http://www.stlchina.org/
Http://www.opensourceproject.org.cn/
Http://www.codeproject.com
Http://www.pudn.com