An internal error occurred during:"Launching .. on tomcat
myeclipse导入一个web工程文件，部署的时候出现An internal error occurred during:"Launching .. on tomcat 6.x 这个问题，detail显示：An internal error occurred during: "Launching ide100cn on Tomcat 6.x".
java.lang.NullPointerException
解决方法：精华就是:关闭myeclipse，删掉.metedate文件夹，重启myeclipse后导入工程。
下面是引用的原文：
If anyone face this problem, first keep in mind that error is not in your code but due to some internal issue in eclipse ADT. I don't know exact problem but luckily found way to solve it. If you ever encounter this error follow steps below:
- Exit Eclipse.
- Go to Android workspace.
- Locate .metadata folder(make sure you set hidden folder visibility on).
- Delete .metedata folder.
- Start Eclipse(you will notice project explorer is empty, don't panic) and import all your projects.