Eclipse “Errors occurred during the build. Errors running builder ‘JavaScript Validator’ on project ‘some-project’. java.lang.NullPointerException”

“Errors occurred during the build.
Errors running builder ‘JavaScript Validator’ on project ‘some-project’.
java.lang.NullPointerException”

At a first sight it seems that a Javascript validator is throwing a NullPointerException, so probably you will try to disable ‘Client-side Javascript’ validation from Project->Properties->Validation… but I tell you that the problem is not there, you must go to Project->Properties->Builders then disable ‘Javascript Validator’.

Problem solved. Indeed is not a real problem, but the message is a bit annoying because it happens in every build so….