Changing the Java version for DMC

Note: This documentation uses version 11.0.8 as an example because the latest version of Java that DMC includes is OpenJDK 11.0.8, 2020-07-14.

If you find any security vulnerabilities with the version of Java that DMC uses, you can replace it with a different 11.x version of Java manually.

Note: Keep a copy of the 11.0.8 java version because you will need it the next time you upgrade the DMC.

To update the Java version for DMC from 11.9=0,=.8 to a different 11.x version, do the following:

Note: fill in <version> with your java version number.

  1. If you are starting from DMC 7.17 and before, skip this step and move on to step 2.
    If you are starting from DMC 7.18 and later, install the freetype fontconfig dejavu-sans-fonts packages by running the yum -y install freetype fontconfig dejavu-sans-fonts; command.
  2. From the terminal, create a directory for your new Java 11.x version by running the mkdir java<version> command.
  3. Navigate to Java with the cd java<version> command.
  4. Download the OpenJDK<version>.tar.gz file for the needed Java 11.x version and put it in your new java<version> directory.

    5. Example: wget https://github.com/AdoptOpenJDK/openjdk11-binaries/releases/download/jdk-11.0.8+10/OpenJDK11U-jre_x64_linux_hotspot_11.0.8_10.tar.gz

    Note: For more information on how to download and install prebuilt OpenJDK packages, see the OpenJDK installation page.

  5. Run the following commands to apply the other Java 11.x version.: 
    6. 
					tar xzf OpenJDK (version).tar.gz	
					sudo datical-control service stop datical-service
					mv /opt/datical/jre /opt/datical/old_jre
					cp /root/java11.xx.xx/jdk-11.xx.xx-jre /opt/datical/jre
					sudo datical-control service start datical-service

Important:
If the Java version was manually changed, you will need to restore DMC's default version of Java (11.0.8) before upgrading DMC. Before upgrading DMC after the Java upgrade, move or copy the previous version of Java (11.0.8) from the /opt/datical/old_jre directory back to the /opt/datical/jre directory prior to upgrading your DMC. DMC expects Java version 11.0.8 to be in the /opt/datical/jre directory for the DMC upgrade process to be successful. After your DMC upgrade is complete, you can change the Java version to a different 11.x java version again.