Junho Park Junho Park - 1 year ago 79
Linux Question

Make $JAVA_HOME easily changable in Ubuntu

In Ubuntu, I'd like to switch my JAVA_HOME environment variable back and forth between Java 5 and 6.

I open a terminal and type in the following to set the JAVA_HOME environment variable:

export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun


And in that same terminal window, I type the following to check that the environment variable has been updated:

echo $JAVA_HOME


And I see /usr/lib/jvm/java-1.5.0-sun which is what I'm expecting to see. In addition, I modify ~/.profile and set the JAVA_HOME environment variable to /usr/lib/jvm/java-1.5.0-sun.

And now for the problem--when I open a new terminal window and I check my JAVA_HOME environment variable by typing in echo $JAVA_HOME I see that my JAVA_HOME environment variable has been reverted back to Java 6. When I reboot my machine (or log out and back in, I suppose) the JAVA_HOME environment variable is set to Java 5 (presumably because of the modification I made in my ~/.profile).

Is there a way around this so that I can change my JAVA_HOME environment without having to log out and back in (AND make that environment variable change stick in all new terminal windows)?

Answer Source

Put the environment variables into the global /etc/environment file:

...
export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun
...

Execute "source /etc/environment" in every shell where you want the variables to be updated:

$ source /etc/environment

Check that it works:

$ echo $JAVA_HOME
$ /usr/lib/jvm/java-1.5.0-sun

Great, no logout needed.

If you want to set JAVA_HOME environment variable in only the terminal, set it in ~/.bashrc file. For More.