The "missing-explicit-ctor" check was disabled by the [JDK-8071961](https://bugs.openjdk.java.net/browse/JDK-8071961) and later was fixed by the [JDK-8250853](https://bugs.openjdk.java.net/browse/JDK-8250853). So we can re-enable this check again.
The fix will remove the "Java.gmk" file and as a result the "jdk.unsupported.desktop" folder. All "Pre-submit tests" builds are green. ------------- Commit messages: - Delete Java.gmk Changes: https://git.openjdk.java.net/jdk/pull/6708/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6708&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8278251 Stats: 26 lines in 1 file changed: 0 ins; 26 del; 0 mod Patch: https://git.openjdk.java.net/jdk/pull/6708.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/6708/head:pull/6708 PR: https://git.openjdk.java.net/jdk/pull/6708
