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)