1. Close eclipse (this method also applies to MyEclipse)
2. Delete the com.genuitec.eclipse.ast.deploy.core.prefs file in the workspace
Absolute path: <workspace directory>/.metadata/.plugins/org.eclipse.core.runtime/.settings/com.genuitec.eclipse.ast.deploy.core.prefs
3. Reopen eclipse
4. In order to facilitate the handling of such problems, you can write a batch to delete automatically. The contents of the batch are as follows:
@echo off The rem eclipise server panel reports an error: java.lang.NullPointerException, restart eclipse after deletion del D:\code\.metadata\.plugins\org.eclipse.core.runtime\.settings\com.genuitec.eclipse.ast.deploy.core.prefs pause