tomcat中的Java Web应用程序会定期冻结

My Java web app running Tomcat (7.0.28) periodically becomes unresponsive. I'm hoping for some suggestions of possible culprits (synchronization?), as well as maybe some recommended tools for gathering more information about what's occurring during a crash. Some facts that I have accumulated:My Java web app running Tomcat (7.0.28) periodi