VM machine, 8GB of RAM, 4 core CPU equivalent

For such setup enabling CMS garbage collector is also recommended. Depending on the traffic usage and particular use-case adjusting NewRatio may be needed (and configuring NewRatio is a must!). Adjusting Xms and Xms sizes for actual available memory is needed (or better yet, for the actual traffic!). Following should be used:

GC="-XX:+UseBiasedLocking -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:NewRatio=2 -XX:+CMSIncrementalMode -XX:-ReduceInitialCardMarks -XX:CMSInitiatingOccupancyFraction=70 -XX:+UseCMSInitiatingOccupancyOnly"
EX="-XX:+OptimizeStringConcat -XX:+DoEscapeAnalysis -XX:+UseNUMA"

#GC_DEBUG=" -XX:+PrintTenuringDistribution -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Xloggc:logs/jvm.log -verbose:gc "

PRODUCTION_HEAP_SETTINGS=" -Xms7G -Xmx7G " # heap memory settings must be adjusted on per deployment-base!