Gradle and Buidship not working for Vaadin project

Thanks a lot !!!
Your suggestions solved my problem.
I have added this little code here to my gradle build file and now the Vaadin application works as expected:

eclipse {
    classpath {
        file {
            whenMerged {
                def src = entries.find { it.path == 'src/main/java' }
                src.output = "/$eclipse.project.name/classes/main-java"
            }
        }
    }
}

Thanks again for your help,
S.