An internal error occurred during: “Updating Maven Project”. java.lang.NullPointerException

1： I solved mine by delete the .settings folder and .project file in the project and then reimport the project

2：For me worked the answer I found on CodeRanch, by user Maneesh Godbole:

Close eclipse.

Navigate to your “workspace” folder

Ensure the setting on your OS to view hidden files is turned on Identify and delete the .metadata directory

Restart eclipse

Import project

3:’ve had the same problem in one of my modules.Running “mvn eclipse:eclipse” in the console/cmd solved the problem for me.

4 : org.eclipse.m2e.core.prefs file is in .settings folder. If you face the problem of

An internal error occurred during: “Updating Maven Project”. java.lang.NullPointerException

Delete the project from eclipse then by deleting the .settings folder & .project file in the project -> then re-import the project.

5 : I had this same issue across multiple projects and multiple workspaces, none of the solutions I found online worked for me. I’m using STS and the only thing that worked was to go into my STS directory and add a “-clean” to the top of the STS.ini file. You can then start up your workspace and run maven clean without errors. (you can also remove the -clean tag from the ini file so it doesn’t clean everytime you start it) Hope this helps someone.

出自：http://stackoverflow.com/questions/19522897/an-internal-error-occurred-during-updating-maven-project-java-lang-nullpoint