Hello, while looking at Tomcat 8.5.61 heap dump in VisualVM, in Dominators by Retained Size, two biggest ones are:
org.apache.tomcat.util.net.NioEndpoint#1 12 382 781 B (13,7%) org.apache.coyote.http11.upgrade.UpgradeGroupInfo#1 7 066 212 B (7,8%) I am wondering about UpgradeGroupInfo, because it has very large array of UpgradeInfos: oname = javax.management.ObjectName#1240 : Catalina:Upgrade=websocket,name="https-jsse-nio-10.8.35.86-8443",type=GlobalRequestProcessor 31 B (0%) 363 B (0%) upgradeInfos = java.util.ArrayList#10079 : 146 098 elements 20 B (0%) 7 066 144 B (7,8%) elementData = java.lang.Object[]#22702 : 160 065 items 640 276 B (0,7%) 7 066 124 B (7,8%) [0] = org.apache.coyote.http11.upgrade.UpgradeInfo#1 44 B (0%) 44 B (0%) Single UpgradeInfo is very small, but there are 146 098 of them. org.apache.coyote.http11.upgrade.UpgradeInfo 146 098 (12,8%) I am not sure what this UpgradeInfo is, it looks like some statistics about upgraded connection, in this case from http to websocket. To me it looks like these UpgradeInfos are not removed when connection is closed. Any comments? Thanks, Harri