Disable RBAC cache in AMQ7 Jolokia to reduce Heap Usage.

RBAC isn't available on AMQ so you can disable the cache. To quickly disable it, open WEB-INF/web.xml in web/console.war with editor and comment out the following <init-param> as follows:

    <!--
    <init-param>
      <param-name>restrictorClass</param-name>
      <param-value>io.hawt.web.RBACRestrictor</param-value>
    </init-param>
    -->

• Have a AMQ7.6 or AMQ 7.5 installation.
• Create a shell script with following content, change USER, PASSWD, URL, BROKER(broker-name) as per AMQ 7.6

  #!/bin/bash
  USER=admin
  PASSWD=admin
  URL=http://localhost:8161
  BROKER=broker1
  while true
  do
          echo "Start Loop"
  curl -X GET --user ${USER}:${PASSWD} -H "Origin: http://localhost:8161" -H "Content-Type: application/json" --insecure $URL/console/jolokia/read/org.apache.activemq.artemis:broker=%22${BROKER}%22
     curl -X GET --user ${USER}:${PASSWD} -H "Origin: http://localhost:8161"  -H "Content-Type: application/json" --insecure $URL/console/jolokia/read/java.lang:type=Memory/HeapMemoryUsage
       curl -X GET --user ${USER}:${PASSWD} -H "Origin: http://localhost:8161"  -H "Content-Type: application/json" --insecure $URL/console/jolokia/read/org.apache.activemq.artemis:broker=%22${BROKER}%22,component=addresses,address=%22DLQ%22/NumberOfMessages
       curl -X GET --user ${USER}:${PASSWD} -H "Origin: http://localhost:8161"  -H "Content-Type: application/json" --insecure $URL/console/jolokia/read/org.apache.activemq.artemis:broker=%22${BROKER}%22,component=addresses,address=%22ExpiryQueue%22/NumberOfMessages
          echo "End Loop"
          sleep 1m
  done
  

• Execute this script and monitor Heap Utilization. Heap Utilization goes to 50% and than minor GC event is able to reduce Heap Utilization. There is no load(no consumer and producers), only jolokia calls for monitoring.