如何在不重启的情况下运行Google App Engine服务器？

I am using Google App Engine plugin with eclipse to create some web application, every time after I modify the program and run it, the modification does not take effect instantly. I have to kill the one (sometime mistakenly will kill the eclipse program) of the javaw.exe process and re-run again. Sometime it will hang at the "datanucleus enhancer". I am using Google App Engine plugin with eclips