I would like to have more insight into "Weak References" and "Class Unloading" phases: http://cr.openjdk.java.net/~shade/shenandoah/stats-purge-weakrefs/webrev.01/ Sample report: http://cr.openjdk.java.net/~shade/shenandoah/stats-purge-weakrefs/gcstats.txt Testing: hotspot_gc_shenandoah -Aleksey