In my J2EE project(Crawler) I've Start and Stop buttons. When I click on Start button Threads'll initialize and starts crawl the pages. Start button works fine. But when I click on stop I want to make them(All Threads) wait(). I'm doing in struts-2. Actually if I want to make them wait() they should hold synchronized blocks. But In my mini-crawler no synchronized blocks are there. I got struck here. Please help me guys.