The VM Options `-XX:AdaptiveSizePausePolicy` and `-XX:ParallelGCRetainPLAB` are obsolete in JDK 9 and are ignored. Use of these options will result in a warning being issued in JDK 9 and they may be removed completely in a future release.

The VM Option `-XX:AdaptiveSizePausePolicy` has been unused for some time.

The VM Option `-XX:ParallelGCRetainPLAB` was a diagnostic flag relating to garbage collector combinations that no longer exist.