Setting the JAVA_HOME environment variable in Ubuntu

Question

I\'m pretty new on ubuntu, at some point in the terminal I\'m running:

mortar local:illustrate pigscripts/retail-recsys.pig purchase_input -f params/retail.p         


        

Answer 1

export JAVA_HOME=/usr/lib/jvm/java-7-oracle

in your ~/.bashrc file.

If you want this environment variable available to all users and on system start then you can add the following to /etc/profile.d/java.sh (create it if necessary):

export JDK_HOME=/usr/lib/jvm/java-7-oracle
export JAVA_HOME=/usr/lib/jvm/java-7-oracle

Then in a terminal run:

sudo chmod +x /etc/profile.d/java.sh
source /etc/profile.d/java.sh

Answer 2

The simplest method to set environment variable is with export:

    $ export JAVA_HOME="/usr/bin"

This will temporarily set the desired variable. You can check if it was set with:

    $ echo $JAVA_HOME

or

    $ printenv

If you want a more permanent solution, append 'export JAVA_HOME="/usr/bin"' to .bashrc or .bash_profile file.

To check if java is properly installed:

    $ which java
    $ which javac

You should get similar output:

    /usr/bin/java

Answer 3

For JAVA_HOME to point to the active jdk, add to your ~/.bashrc

export JAVA_HOME=$(update-alternatives --query javac | sed -n -e 's/Best: *\(.*\)\/bin\/javac/\1/p')

which will dynamically set the $JAVA_HOME to the JDK selected by update-alternatives.