An error exception occurred during Eclipse startup: An internal error occurred during: "Initializing Java Tooling". The solution to java.lang.NullPointerException

unusual phenomenon:

Open Eclipse, an error pop-up box appears, An internal error occurred during: "Initializing Java Tooling". java.lang.NullPointerException;

Reason:

An error that occurs when eclipse is closed unreasonably;

Solution:

Delete the .project file under the program's workspace

Specific path:

workspace\.metadata\.plugins\org.eclipse.core.resources\.projects