This compilation unit is not on the build path of a Java project

If you ever face this issue in eclipse, you have to add the below java natures in .project file, which is available in your project's home directory. After adding these lines restart your eclipse. It should work !!!


.project file :
---------------

        <natures>
<nature>org.sonar.ide.eclipse.core.sonarNature</nature>
<nature>org.eclipse.jdt.core.javanature</nature>
<nature>org.eclipse.m2e.core.maven2Nature</nature>
</natures>