Java Developers Guide: How to set java version in Linux

20 November, 2016

How to set java version in Linux

How to set java version in Linux or Unix.

Here I have used Linux Mint, but this setup can work for other Linux distributions.

Checking the existing java version on your linux machine.
dev@developer-desktop ~ $ java -version
java version "1.6.0_36"
OpenJDK Runtime Environment (IcedTea6 1.13.8) (6b36-1.13.8-0ubuntu1~12.04)
OpenJDK 64-Bit Server VM (build 23.25-b01, mixed mode)

The above command shows the existing java version installed on this machine. Now I can check the alternative version to set. These alternative versions are available for installation. The below command will prompt with sudo password and selection number. Try with below command :

dev@developer-desktop ~ $ sudo update-alternatives --config java
[sudo] password for dev: ***********
There are 3 choices for the alternative java (providing /usr/bin/java).

Selection    Path                                            Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   1061      auto mode
1            /usr/bin/gij-4.6                                 1046      manual mode
2            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   1061      manual mode
3            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1051      manual mode

Press enter to keep the current choice[*], or type selection number: 3
update-alternatives: using /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java to provide /usr/bin/java (java) in manual mode.

In the above command, I have opted the Selection 3 , because I want java 1.7 version. You can choose as per your requirements.

Now you can check whether version 7 is installed or not ? Try the check version command again as below.

dev@developer-desktop ~ $ java -version
java version "1.7.0_79" -----> This is newly installed.
OpenJDK Runtime Environment (IcedTea 2.5.6) (7u79-2.5.6-0ubuntu1.12.04.1)
OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)

Hope this will help you.