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:

1. Close eclipse.
2. Navigate to your “workspace” folder
3. Ensure the setting on your OS to view hidden files is turned on Identify and delete the .metadata directory
4. Restart eclipse
5. 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