To install Java on an Ubuntu Linux system:
Make sure that the repository library is up to date.
sudo apt update
Perform a search for the OpenJDK packages that are available.
sudo apt search openjdk
The package list displayed will look like the below. You need to choose one depending on which Java version you want, whether you want the
JRE
(for running applications) orJDK
(for developing them), "normal" (for interactive Java apps) or "headless" (for running on a server with no user interactivity), etc.openjdk-13-jdk-headless/focal-updates 13.0.7+5-0ubuntu1~20.04 arm64
OpenJDK Development Kit (JDK) (headless)
openjdk-13-jre/focal-updates 13.0.7+5-0ubuntu1~20.04 arm64
OpenJDK Java runtime, using Hotspot JIT
openjdk-8-jdk-headless/focal-updates,focal-security 8u312-b07-0ubuntu1~20.04 arm64
OpenJDK Development Kit (JDK) (headless)
openjdk-8-jre/focal-updates,focal-security 8u312-b07-0ubuntu1~20.04 arm64
OpenJDK Java runtime, using Hotspot JIT
openjdk-8-jre-headless/focal-updates,focal-security 8u312-b07-0ubuntu1~20.04 arm64
OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-8-jre-zero/focal-updates,focal-security 8u312-b07-0ubuntu1~20.04 arm64
Alternative JVM for OpenJDK, using Zero/Shark
Once you've chosen a Java package, install it.
sudo apt install openjdk-8-jre-headless
Verify the installation was successful.
java -version
The output should look like this, depending on the package you installed.
openjdk version "1.8.0_312"
OpenJDK Runtime Environment (build 1.8.0_312-8u312-b07-0ubuntu1~20.04-b07)
OpenJDK 64-Bit Server VM (build 25.312-b07, mixed mode)