How to check all available Java versions on Linux

In order to check the list of Java versions available on our Linux machine, we can use the following command.

$ sudo update-alternatives --config 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

  3            /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java   1081      manual mode

The one with * indicates the current version. We can check the current Java version being used directly as well.

$ java --version

openjdk 17.0.10 2024-01-16

OpenJDK Runtime Environment (build 17.0.10+7-Ubuntu-122.04.1)

OpenJDK 64-Bit Server VM (build 17.0.10+7-Ubuntu-122.04.1, mixed mode, sharing)