free command shows Java process size much smaller than the initial heap size

Issue

• Tomcat is starting with the initial and max heap set to 6144m; however, free output shows memory usage far below the initial heap size:

$ ps -ef | grep -i java
tomcat85      7      1 73 17:52 pts/0    00:00:51 /etc/alternatives/jre/bin/java -Xms6144m -Xmx6144m org.apache.catalina.startup.Bootstrap start

# free -m 
              total        used        free      shared  buff/cache   available
Mem:          15866         775       13180          11        1910       14757
Swap:          4515           0        4515