why i can debug servlet, but can't debug servlet's action

HI all:
   I have included tomcat's Bootstrap.java in my source, and included all runtime jar, and then i execute jde-debug command on Bootstrap.java, tomcat start up OK, i continue to setting breakpoint in HelloWorldServlet, it debug OK.
   Next i create copy of same environment, with adding Spring + WebWork + Hibernate framework. When i jde-run Bootstrap.java, all execute OK.  But when i jde-debug Bootstrap.java, setting breakpoint in a WebWork's Action execute() method. When i request that action, the action didn't hung, and continue to finish, Brower displayed OK. 
   Why JDEE can't hang the Action?

       	    	       Peter