Installing Java walkthrough

1. Check that the required version of Java is installed

java -version

Possible outcomes

Correct version (`17..`)

# java -version
openjdk version "17.0.12" 2024-07-16
OpenJDK Runtime Environment (build 17.0.12+7-Ubuntu-1ubuntu220.04)
OpenJDK 64-Bit Server VM (build 17.0.12+7-Ubuntu-1ubuntu220.04, mixed mode, sharing)

Command not found

# java -version
java: command not found

This indicates Java is not installed. To install Java, run the following command:

apt install openjdk-17-jdk

Old version installed

# java -version
openjdk version "11.0.24" 2024-07-16
OpenJDK Runtime Environment (build 11.0.24+8-post-Ubuntu-1ubuntu320.04)
OpenJDK 64-Bit Server VM (build 11.0.24+8-post-Ubuntu-1ubuntu320.04, mixed mode, sharing)

This indicates you are running an older version of Java. To resolve the issue, install Java 17 using the following command:

apt install openjdk-17-jdk

Verify the Java version is now using version 17. If the old version is stil being used, update to the new version by following the prompts of the following command:

update-alternatives --config java

# update-alternatives --config java
There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                         Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-17-openjdk-amd64/bin/java   1711      auto mode
* 1            /usr/lib/jvm/java-11-openjdk-amd64/bin/java   1111      manual mode
  2            /usr/lib/jvm/java-17-openjdk-amd64/bin/java   1711      manual mode

Press <enter> to keep the current choice[*], or type selection number: