Hi!
I'm not a Java person, so I'm sorry if I'm asking nonsense 
Recently we upgraded ES to version 6.6.1 and Java to version 11. So I'm wondering what GC is now used - CMS, as before, or G1. I'm asking because I see G1 is mentioned multiple times in /_nodes/ output.
Our jvm.options file:
-Dfile.encoding=UTF-8
-Dio.netty.noKeySetOptimization=true
-Dio.netty.noUnsafe=true
-Dio.netty.recycler.maxCapacityPerThread=0
-Djava.awt.headless=true
-Djna.nosys=true
-Dlog4j.shutdownHookEnabled=false
-Dlog4j2.disable.jmx=true
-XX:+AlwaysPreTouch
-XX:+HeapDumpOnOutOfMemoryError
-XX:+UseCMSInitiatingOccupancyOnly
-XX:-OmitStackTraceInFastThrow
-XX:CMSInitiatingOccupancyFraction=75
-Xlog:gc*:file=/var/log/elasticsearch/es-01/gc.log::filecount=10,filesize=4096
-Xlog:gc+age=trace
-Xlog:safepoint
-Xms15g
-Xmx15g
-Xss1m
-server
Thank you!