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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.

Next steps​

  • Open source tracing

    Depending on the framework or open source library used in applications, you may need to add agent options. For example, when using spring-boot-3.x, feign-client-11, or okhttp3-4.4 with a framework or open source, set the options as follows:

    whatap.conf
    weaving=spring-boot-3.0,feign-11,okhttp3-4.4

    For information on how to configure the framework or open source library that suits your application environment, see the following.

  • Checking the installation

    If you have created a project, installed an agent, and applied all JVM options, see the checklist in the following.

  • Installation troubleshooting

    It provides various problems that may occur when installing the agent and specific instructions for resolving them. It provides solutions against various situations, including firewall configuration, SpringBoot and Tomcat JMX configuration, and server configuration using the OSGI framework. For more information, see the following.

  • Agent setting

    It provides various features for monitoring by applying some options to the agent configuration file (whatap.conf). It includes basic configuration, configuration for server connection and data transfer, how to manage the configuration files for multiple application servers, and transaction tracing, and more. For more information, see the following.

  • Starting the monitoring

    After all settings are made, restart the application server. The agent starts collecting data. First, check whether the monitoring data has been collected in Application Dashboard. For more information about Application Dashboard, see the following.