The method testOverlapWithBaseModule in jdk/modules/scenarios/overlappingpackages/OverlappingPackagesTest.java obviously doesn't test what it is supposed to test. The wrong command line parameter "-add-modules" is passed to a child process, instead of "--add-modules". A nonzero exit value is asserted but it should not happen due to the bad command line parameter as it does right now. It rather should fail due to an incorrect package overlap.