http://www.ibm.com/developerworks/cn/java/j-enums.html
http://www.ibm.com/developerworks/cn/java/j-tiger04195
http://dev2dev.bea.com.cn/techdoc/20060105718.html
http://www.ibm.com/developerworks/cn/java/j-tiger04195
http://dev2dev.bea.com.cn/techdoc/20060105718.html