After upgrading a Grails application from 2.2.0 to 2.2.1 I keep getting the following error when attempting to debug a Grails application from GGTS via Debug as... -> Grails
I had the same exception, when I was trying to run JUnit tests on my Spring boot project in Eclipse only, mvn executes them fine. I'm not using Gradle or Groovy. Indeed checking the test's class path upon debug, showed two versions of groovy.jar. The work version of the groovy.jar was picked from other projects in the Eclipse workspace. I was able to fix it by removing Resolve dependencies from Workspace projects in project properties -> Maven