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Play2

Adding JVM options​

This explains how to add required JVM options to effectively use the Java monitoring agent in the Play2 application server environment.

Set the agent options in the $PLAY_HOME/framework/build file. If you have a separate startup or stop script, apply it to that file.

#! /usr/bin/env sh

########## WHATAP START ############
WHATAP_HOME=/apps/whatap
WHATAP_JAR=`ls ${WHATAP_HOME}/whatap.agent-*.jar | sort -V | tail -1`
JAVA_OPTS="${JAVA_OPTS} -Dwhatap.play2=2.2.6 -javaagent:${WHATAP_JAR}"
########## WHATAP END ############

if [ -z "${PLAY_VERSION}" ]; then
  PLAY_VERSION="2.2.6"
...
Note

For Play, add the -Dwhatap.play2=2.2.6 option other than the default settings.

Note

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


--add-opens=java.base/java.lang=ALL-UNNAMED

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

    -Djdk.attach.allowAttachSelf=true
    example
    java -javaagent:{WHATAP_HOME}/whatap.agent-X.Y.Z.jar -Djdk.attach.allowAttachSelf=true -jar {application.jar}

  • Java 16 or later

    -Djdk.attach.allowAttachSelf=true
    --add-opens=jdk.attach/sun.tools.attach=ALL-UNNAMED
    example
    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/sun.tools.attach=ALL-UNNAMED -jar {application.jar}
Note

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.