Errors running builder 'Android Resource Manager' on project 'project name'. java.lang.NullPointerException

You may get the error while compiling the Android app "Errors running builder 'Android Resource Manager' on project 'lock'. java.lang.NullPointerException". You could also get this error while creating a project and you wouldn't be able to create the project altogether.

There could be multiple reasons for the error : 

• Your project file might be missing
• The dependent project library might be missing or
• You might be building an app with Activity but the respective API SDK might not be installed 

If above are not the reasons then you might want to check out this