In case of low heap, a suggestion is printed to enable CMS GC, but doing so causes Java to print the following warning:

OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.

According to http://openjdk.java.net/jeps/291, the suggestion is to use UseG1GC instead..