How to set JAVA_HOME for Java?

Solution 1:

You can set your JAVA_HOME in /etc/profile as Petronilla Escarabajo suggests. But the preferred location for JAVA_HOME or any system variable is /etc/environment.

Open /etc/environment in any text editor like nano or gedit and add the following line:

JAVA_HOME="/usr/lib/jvm/open-jdk"

(java path could be different)

Use source to load the variables, by running this command:

source /etc/environment

Then check the variable, by running this command:

echo $JAVA_HOME

Update

Usually most linux systems source /etc/environment by default. If your system doesn't do that add the following line to ~/.bashrc (Thanks @pje)

source /etc/environment

Solution 2:

To set JAVA_HOME environment variable, do the following:

1. Launch Terminal by pressing Ctrl+Alt+T on your keyboard.
2. Enter the following command:
   $ gksudo gedit /etc/environment
3. Depending on where you installed your Java, you will need to provide the full path. For this example, I installed Oracle JDK 7 in the /usr/lib/jvm/java-7-oracle directory.
   Scroll to the end of the file and enter the following:
   JAVA_HOME=/usr/lib/jvm/java-7-oracle
export JAVA_HOME
4. Save your file and exit gedit.
5. Lastly, reload the system PATH with the following command:
   $ . /etc/environment

The above method will save you the hassle in having to run the commands every time you log in to your computer.

Solution 3:

If you do not know the path and you only have openJDK installed, you can type update-alternatives --config java and you should find the path. To set the variable you can write JAVA_HOME=<PATH> followed by export JAVA_HOME. Notice there's no space when declaring the variable. To check if the variable is stored you simply type echo $JAVA_HOME to verify.