Recompilation of class packages in WEB-INF in myeclipse

During project development, using the automatic prompt function of myeclipse sometimes imports unused jar packages, and forcibly deletes unused packages (for example, in the resource manager, deleting In the lib directory will cause the problem that the class package in the WEB-INF cannot be re-compiled (that is, after the class folder is deleted, it cannot be re-compiled ). The error message is displayed, indicating that the jar import path has an error.

The solution is to right-click the project, select the deleted jar package from Java build path libraries, and click Remove. Generally, the class file cannot be compiled properly due to the deletion of the jar package.