How to Set the JAVA_HOME Environment Variable on Debian-Based Linux for OpenJDK?

What is the correct target for the JAVA_HOME environment variable for a Linux OpenJDK Debian-based distribution?

Configuring the JAVA_HOME environment variable correctly in a Debian-based distribution, such as Kubuntu, is essential for running Java applications smoothly, especially when dealing with different file locations for executables and libraries.

export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
export PATH=$JAVA_HOME/bin:$PATH
# Add JAR files manually if needed
export CLASSPATH=$JAVA_HOME/lib/*

Causes

• Java executables are located in `/usr/bin`
• Java libraries (JAR files) are stored in `/usr/share/java`

Solutions

• Set JAVA_HOME to `/usr/lib/jvm/java-*`, where `*` matches your installed OpenJDK version.
• Ensure that the necessary binary paths are included in your system's PATH variable.

Mistake: Setting JAVA_HOME to `/usr` or `/usr/share/java` directly.

Solution: JAVA_HOME should point to the JDK installation path like `/usr/lib/jvm/java-11-openjdk-amd64`.

Mistake: Not including JAVA_HOME/bin in the PATH variable.

Solution: Make sure to add `export PATH=$JAVA_HOME/bin:$PATH` to your `.bashrc` or `.bash_profile`.