Switching between Java versions in Debian based distributions

Switching between installed Java versions can be accomplished using the update alternatives command.

To get a list of your installed Java platforms, run the following command from the terminal:

sudo update-alternatives --config java

This will give you a list output similar to this:

There are 2 choices for the alternative java (providing /usr/bin/java).
   Selection                             Path                                   Priority         Status
  ---------------------------------------------------------------------------------------------
  0            /usr/lib/jvm/java-8-oracle/jre/bin/java                1081            auto mode
*1            /usr/lib/jvm/java-7-openjdk-i386/jre/bin/java    1071       manual mode
  2           /usr/lib/jvm/java-8-oracle/jre/bin/java                 1081       manual mode
Press enter to keep the current choice[*], or type selection number:

In this case, the Open JDK 6 version is running. To switch to the Open JDK version 7, you would select option 1 at the prompt and press the Enter key.

You will now be running the OpenJDK 7 version. No other changes will be needed to switch your Java versions.