VM machine with 4GB or less of RAM, and less than 4 core CPU equivalent

Small installations with limited resources could operate better with default (for JVM versions up to 8, which is the most current at the moment of the writing). Again - depending on the traffic usage and particular use-case adjusting NewRatio may be needed. Adjusting Xms and Xms sizes for actual available memory is recommended (or better yet, for the actual traffic!). Following should be used (i.e. GC line should be commented so the defaults will 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=" -Xms3G -Xmx3G " # heap memory settings must be adjusted on per deployment-base!