So far, the biggest problem I encounter is the hot deployment of web application to Tomcat. I always have to restart the server to do redeployment. The server always hold some jar file which myeclipse fail to delete hence fail to redeploy.

recently I redeploy a web appliation and myeclipse complain about the standard.jar being locked, clearly the library do not need to be deleted. Can myeclipse improve so that it delete only the files has been modified to minimize the chance that hot deployment failure?

This is exactly what happens when you use an "Exploded deployment", the changes are copied out immediately after you save the file... just make sure ot have Tomcat setup to reload the changes (might take up to 15 seconds).

Thanks for the reply. If I understand correctly, you mean I don't need to manually do redeployment, I just need to save the changes, wait for some seconds, and then go to browser to test and it will reflect my changes. sounds nice. seems it works somehow. of course, sometimes still have to restart. but, anyway, it is good enough.

Yep you got it, when you DO have to restart is when Tomcat is unable to cleanly reload the changed classes (if the structure chanegs too much, it can't). However, you can keep the Tomcat manager open in another browser window and just click "Restart" next to the context you are working on, this will allow you to avoid restarting the entire application server.