JOC Cockpit installation throws error when installed with Java 21 for Ubuntu

Current Behavior

• Running the installer for JOC Cockpit using Java 21.0 for Ubuntu fails with the following error message as:

  Command line arguments: joc_install.xml
  SEVERE: java.lang.ArrayIndexOutOfBoundsException: Index 70131 out of bounds for length 22674
  -- end of log ----------------

Known Issue

• This is a known problem in Ubuntu as indicated for example with https://izpack.atlassian.net/jira/software/c/projects/IZPACK/issues/IZPACK-1786
• The problem is reported for the Ubuntu platform using Java 21.0. The problem does not reproduce for RedHat, CentOS etc. using Java 21.0.
  • The problem is related to the Ubuntu Java package when installing Java 21. Java doesn't need an installer: if Java 21 is just downloaded and is stored to a directory then this works fine with JOC Cockpit. See Workaround.
• The solution for the Ubuntu Java package probably will come from an update of Ubuntu or Java.

Workaround

• Users who face the above problem can fall back to use of Java 17
• Users can download Java without use of the Ubuntu package manager.
  • Use of the Ubuntu Java package will raise the error:

    # update from universe repository
    apt install openjdk-21-jre
    

  • Downloading Java will prevent the error:

    # download and extract Temurin Java from Eclipse (adjust paths to your needs)
    cd /opt/java
    curl -L https://github.com/adoptium/temurin21-binaries/releases/download/jdk-21.0.5%2B11/OpenJDK21U-jdk_x64_linux_hotspot_21.0.5_11.tar.gz -O
    tar xzf OpenJDK21U-jdk_x64_linux_hotspot_21.0.5_11.tar.gz
    
    # add Java location to PATH and JAVA_HOME
    export PATH=/opt/java/jdk-21.0.5+11-jre/bin:$PATH
    export JAVA_HOME=/opt/java/jdk-21.0.5+11-jre
    
    # run the JOC Cockpit installer
    

  • Both Java versions of the Ubuntu Java package and of Eclipse Temurin are the same (at the time of writing). However, they are packaged in different ways.