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Adding JVM options

The following explains how to add required JVM options to effectively use the Java monitoring agent in the Liberty application server environment.

In the jvm.options file, add the agent option. If no file, create a new one.

-Dorg.osgi.framework.bootdelegation=whatap.* ## Additional options for OSGI framework configuration ##

In case of Java 17 or later, add the following options for reflection.


Viewing the heap histogram

WhaTap's Java Monitoring provides the function to view the status of heap occupancy objects in the JVM memory (sizes for each object in heap memory). In APP > Instance performance analysis, select the Heap histogram tab.

Java versions 6 to 8 support basic functions without the JVM options. However, for some Java versions, the JVM options must be applied as follows:

  • Java 9 to Java 15

    java -javaagent:{WHATAP_HOME}/whatap.agent-X.Y.Z.jar -Djdk.attach.allowAttachSelf=true -jar {application.jar}
  • Java 16 or later

    java -javaagent:{WHATAP_HOME}/whatap.agent-X.Y.Z.jar -Djdk.attach.allowAttachSelf=true --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=jdk.attach/ -jar {application.jar}

It does not support Java 5 or earlier and IBM Java.

Starting the monitoring

Once the application server is restarted after configuring all settings, the agents start collecting data. See the following.