Install Open JDK 11 on Debian 12 (Bookworm)

In Debian 12 the default JDK is Java 17. In case you need Java 11 instead you can follow this blog from Linux Shout .

Here is the short version:

1) Edit your sources.list

Edit the file /etc/apt/sources.list and add the unstable packages at the end of the file

deb http://deb.debian.org/debian unstable main non-free contrib

2) Next Update your apt preferences

Edit the file /etc/apt/preferences and add the following entry:

Package: *
Pin: release a=stable
Pin-Priority: 900

Package: *
Pin: release a=unstable
Pin-Priority: 50

This will make our Debian 12 system only choose the stable packages while updating instead of unstable ones.

3) Install JDK 11

Now you can install JDK 11 and switch the java version using the

$ sudo apt update
$ sudo apt install openjdk-11-jdk
$ sudo update-alternatives --config java

The last command allows you to switch between JDK 17 and JDK 11.