Windows

Install new Java version

Follow instructions to install Java: Install Java

Update JAVA_HOME

If you have set the environment variable JAVA_HOME, check whether this needs updating. Commonly this will be automatically updated by the installation process.

Update service wrapper

Find the file jvm.dll in the Java installation.

• Java 8: this will be in JAVA_HOME\jre\bin\server\jvm.dll

• Java 11: this will be at JAVA_HOME\bin\server\jvm.dll

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

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

Remove old version

Installation of a new patch of Java should remove the previous version, but you should confirm that 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.

Linux

Install new Java version

Follow instructions to install Java: Install Java

Update JAVA_HOME

If you have followed the standard installation instructions, you have already done this.

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

Delete the previous installation

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

For example

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