To set the JAVA_HOME environment variable, first, discover where Java is installed by running the following command. Most of the Java-based software programs use the JAVA_HOME environment variable to discover the Java installation location. Setting the JAVA_HOME Environment Variable in Ubuntu You will get the following output: javac 11.0.10 $ sudo apt install default-jdkĪfter installation, verify the JDK installation by checking the version as shown. To install the JDK, run the following command. Once JRE installed, you might also need the JDK ( Java Development Kit) in order to compile and run a Java-based application. OpenJDK 64-Bit Server VM (build 11.0.10+9-Ubuntu-0ubuntu1.20.04, mixed mode, sharing) OpenJDK Runtime Environment (build 11.0.10+9-Ubuntu-0ubuntu1.20.04) You will get the following output: openjdk version '11.0.10' Once Java installed, you can verify the installation with: $ java -version

Now run the following command to install the default OpenJDK 11, which will provide Java Runtime Environment ( JRE). Sudo apt install openjdk-8-jre-headless # version 8u282-b08-0ubuntu1~20.04 Sudo apt install default-jre # version 2:1.11-72 Command 'java' not found, but can be installed with: If Java is not currently installed, you will get the following output.

Ubuntu install openjdk 11