Windows

Stop Tomcat

See Managing Tomcat

Install new Java version

Follow instructions to install Java: Install Java

Update JAVA_HOME

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Setting JAVA_HOME is not part of the standard installation of Java for PhixFlow, but some operators set this for use with other programs on the same server.

If someone has set the environment variable JAVA_HOME, check whether this needs updating in the system environment variables. Commonly this will be automatically updated by the installation process.

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Open Tomcat Properties window. If you need further details on how to open this, see: Managing Tomcat start/ stop, open properties

Go to the Java tab. Update the Java Virtual Machine setting to the new location of jvm.dll.

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If you have moved between major versions of Java (e.g. you are moving from Java 8 to Java 11), update the Java arguments as instructed here: Install Tomcat on Windows

Remove old version

Installation of a new patch of Java should remove the previous version, but you should confirm that replace the previous version has been removed by examining the list of installed programs.

If you are migrating to a new major version of Java (e.g. you are moving from Java 8 to Java 11), you will need to remove the previous version from the list of installed programs.

Start Tomcat

See Managing Tomcat

Linux

Stop Tomcat

See Managing Tomcat

Minor (patch) upgrades

If you have installed Java as recommended by PhixFlow (Install

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Follow instructions to install Java: Install Java

Update JAVA_HOME

If you have followed the standard installation instructions, you have already done thisJava), upgrade Java as recommended for any package installed using the package manager. For example, on Debian based distributions of linux, the generally recommended approach is by using dist-upgrade.

Major upgrades

If you are upgrading between major versions of Java, you will need to remove the current installation of Java, and install the new version.

Remove the existing Java installation using the standard method for packages installed using the package manager. For example, on Debian based distributions, to remove Java 8 Adoptium OpenJDK, use the commands:

sudo apt-get remove temurin-8-jdk
sudo apt-get purge --auto-remove temurin-8-jdk

Then install the new version of Java using the instructions given at Install Java, starting from sudo apt-get update (you do not need to re-install or update the Adoptium repository).

Update service script

Open the tomcat service script at /etc/systemd/system/tomcat.service

Update JAVA_HOME in the script to the value of $JAVA_HOME in your environment. You must make this the full path for the Java installation, you cannot refer to the environment variable in the script. The resulting file will look similar to this:

[Unit]
Description=Apache Tomcat Web Application Container
After=network.target

[Service]
Type=forking

Environment=JAVA_HOME=/opt/jdk/jdk-11.0.13+8
Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat

Remove old version

If you installed Java following PhixFlow’s recommended installation (Install Tomcat on Linux), delete the previous installation

cd /opt/jdk
sudo rm -r [PREVIOUS VERSION]

For example

sudo rm -r /opt/jdk/jdk-11.0.13+8

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You may need to update the JAVA_HOME setting in the service script for Tomcat.

To find the new setting, run the command:

update-alternatives --list java

This will give you the full path of the java program, for example: /usr/lib/jvm/temurin-11-jdk-amd64/bin/java. The installation directory in this case is /usr/lib/jvm/temurin-11-jdk-amd64.

Check whether this is different from the current setting of JAVA_HOME in /etc/systemd/system/tomcat.service. If this is different, update /etc/systemd/system/tomcat.service to use the new setting for JAVA_HOME, and before you restart the tomcat process, run the command:

sudo systemctl daemon-reload

Moving from Java 8 to Java 11

If you have moved from Java 8 to Java 11, update CATALINA_OPTS in /etc/systemd/system/tomcat.service for the the new logging settings at that version of Java, as instructed here: Install Tomcat on Linux

Start Tomcat

See Managing Tomcat