Errors occurred during the build. Errors running builder 'GWT Project Validator'

Question

Hi i am new in GWT and just installed eclipse photon and imported the project. Whenever i try to build the project i get the error

"Errors occurred during the build.<br>
Errors running builder 'GWT Project Validator' on project 'myProject'.
org.eclipse.jdt.internal.core.JavaProject.computePackageFragmentRoots([Lorg/eclipse/jdt/core/IClasspathEntry;ZLjava/util/Map;)[Lorg/eclipse/jdt/core/IPackageFragmentRoot;"

There was no such error in Eclipse neon and the project is developed in older version then neon . And there is no errors in eclipse error log just warnings.

Any suggestions....

Answer 1

Are you sure there was no stack trace (NoSuchMethodError?) associated with the error messages you posted? If so, this looks like a known issue with Eclipse Oxygen (4.7.1a+), so presumably it also impacts Photon:

Eclipse Oxygen 4.7.1a introduced the issue. The GWT Eclipse plugin was using an internal api, which was faster, but the internal api change broke. I thought I fixed this. I don't think it matters which version of GWT you're using.

If that Bug Report fits matches the symptoms of your failure it would be helpful for you to update that bug report, mentioning that you are seeing the same problem with Photon. In the meantime you will have to regress that project to Neon. It looks like you could also use a release of Oxygen prior to 4.7.1a but I doubt if early versions of Oxygen are still available for download.

However, if you are not seeing a NoSuchMethodError please build your project again and update your post with the content of the Error Log. There has to be more information beyond the three lines shown in the OP.