Error logging--resource xxxx does not exist problem resolution

Using WTP to develop Web programs, you need to remove a jar library under Web-inf/lib, which is not erased in Eclipse's Project Explorer because it's in BuildPath. So you turn eclipse off and then you find it through the Explorer

That project's folder, delete the file. To reopen Eclipse and run the Web program (run on server), a publishing failed error appears, with the details: Resource/xxxx does not exist, whose

The/xxxx is the project folder. How could it be that the folder was well placed there, and actually said does not exist.
Cause: Because of the deletion of a jar outside, Eclipse does not know yet, when the Web application was published to think that the jar is still there, so it was released, but the file does not exist, so the error. It's just that this is a wrong newspaper.

If a file is missing, the whole project does not exist, misleading.
WORKAROUND: Delete the jar without deleting it directly in Eclipse, and not on the outside. To remove the entire Web library from the BuildPath, all the jars in Lib are not in the BuildPath, and then in Eclipse's

Project Explorer (Navigator view) to remove the jar and then add the Web Library.