We run many Tomcat servers and have observed full garbage collections (GCs) are often performed on an hourly basis, particularly when memory usage is relatively low. The precise
you should be able to change the interval by
-Dsun.rmi.dgc.client.gcInterval=60000 -Dsun.rmi.dgc.server.gcInterval=60000
take a look here https://docs.oracle.com/cd/E19199-01/817-2180-10/pt_chap5.html