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Tomcat

Adding the boot environment​

This guide explains how to add required Tomcat options to effectively use the Java monitoring agent in the WebLogic application server environment. Set it according to the operating system.

Linux​

At the top of the catalina.sh file, add the JAVA_OPTS environment variable.

{Tomcat_PATH}/bin/catalina.sh
########## WHATAP START ############
WHATAP_HOME=/whatap
WHATAP_JAR=`ls ${WHATAP_HOME}/whatap.agent-*.jar | sort -V | tail -1`
JAVA_OPTS="${JAVA_OPTS} -javaagent:${WHATAP_JAR} "
########## WHATAP END ############
Note

The ls ${WHATAP_HOME}/whatap.agent-*.jar | sort -V | tail -1 entry is used to apply the latest WhaTap agent for future update.

Windows​

  • In case of running the setup.bat file

    At the top of the catalina.bat file, add the JAVA_OPT environment variable.

    {Tomcat_PATH}/bin/catalina.bat
    rem ########## WHATAP START ############
    set WHATAP_HOME=C:\whatap
    for /f %%f in ('dir /b /on "%WHATAP_HOME%\whatap.agent-*.jar"') do set last=%%f
    set WHATAP_JAR=%last%
    set WHATAP_OPTS=-javaagent:%WHATAP_HOME%\%WHATAP_JAR%

    if "x%JAVA_OPTS%"=="x" goto setWhatap

    set JAVA_OPTS_TMP=%JAVA_OPTS:"=%
    if not "x%JAVA_OPTS_TMP:whatap=%"=="x%JAVA_OPTS_TMP%" goto endWhatap

    :setWhatap
    set JAVA_OPTS=%JAVA_OPTS% %WHATAP_OPTS%

    :endWhatap
    rem ########## WHATAP END ############

  • In case tomcat has been installed with the Windows installer

    1. Select Start > Apache Tomcat X.Y.Z. > Configure Tomcat.

    2. Select the Java tab.

    3. Add the -javaagent option to the Java Options field.

    -javaagent:{WhaTap installation path}/whatap.agent-X.Y.Z.jar

    Apache Tomcat

Java 17 or later​

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.