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I've installed a version of Java. How can we set the $JAVA_HOME environment variable correctly?

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up vote 104 down vote accepted

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

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
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2  
I'm getting: JDK Required: 'tools.jar' seems to be not in IDEA classpath. Please ensure JAVA_HOME points to JDK rather than JRE. – anon58192932 Mar 21 '14 at 21:31
1  
@advocate - You should probably post your own question for that. But the clue is in the message; you need to point at a JDK not a JRE. – David Edwards Mar 28 '14 at 14:57
    
@DavidEdwards Apparently my JDK wasn't even installed :) Installed open JDK 7 with the package manager and all was good! I'm working with a foreign Ubuntu build so wasn't sure the extent to which it was set up. – anon58192932 Mar 28 '14 at 18:46
1  
When i tried to run Android Studio (that has IntelliJ IDEA as a base), i had an error message very similar to @advocate's: "'tools.jar' seems to be not in Android Studio classpath." After fiddling a lot with JAVA_HOME without success, i decided to take a look at studio.sh, the shellscript that starts Android Studio. As a wild guess, i set JDK_HOME to the same value expected for JAVA_HOME, and voila! It installed without great problems. – Hilton Fernandes Mar 7 '15 at 23:20
    
how to set multiple paths for different JDKs paste.ubuntu.com/13151297 will work?? – LOG_TAG Nov 7 '15 at 17:13

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.

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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.

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This seems like it would be static. If I remove openjdk-7 and install openjdk-9, won't the JAVA_HOME then point to the wrong place? How can it be made dynamic? – DavidJ Jul 20 at 18:49

protected by Community Mar 8 '15 at 7:48

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