Need Help on JAVA_HOME, CLASSPATH set up

[DapperDrakeNewbieDR]

I need step-by-step instructions on how to set up the JAVA_HOME and CLASSPATH variables. Can anyone help me out with this issue?

Thanks in advance.

[tedwardo2]

it depends on what implementation of java you have installed, where it is installed, and a number of other things.

If you already know what you want to set JAVA_HOME and CLASSPATH to, you can just run

sudo gedit /etc/environment

and then add a line for each variable.

[DapperDrakeNewbieDR]

Thanks tedwardo2, it worked perfectly fine.

See you around.

[DapperDrakeNewbieDR]

This is the output of the "etc/environment" file after I "gedit" it,

PATH="/usr/local/Java/jdk1.5.0_07/bin:.:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin/X11:/usr/games"
LANG="en_AU.UTF-8"
LANGUAGE="en_AU:en"
JAVA_HOME="/usr/local/Java/jdk1.5.0_07"
CLASSPATH="/usr/local/Java/jdk1.5.0_07/lib:."

It may serve you as a guide to you folks looking for help.

[erpa]

i'm having the same problem, but i don't know exactly what to do. i installed jdk and jre trough apt-get but i can't find "/usr/local/Java/jdk1.5.0_07/bin:." or any of the others path you used.
The best i was able to do was to find the java folder in usr/share but i can't find anything like jdk1.5.0_07/bin:. in it. This is the content of the java folder :



wich path should i use? doi need to install somtging else? atm the content of my etc/environment is:

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
LANG="it_IT.UTF-8

thx in advice for help

P.S. sry for may bad english

[steve.horsley]

The easiest way to find it is to use the command
whcih java
which probably says /usr/bin/java, but this is a symlink. if you do
ls -l /usr/bin/java
it will tell you where it links to (probably another symlink). Keep on followinf the symlinks until you find the real executable. It's there somewhere.

If you install java straight from Sun, it defaults into /opt/java..., but the Ubuntu packagers tend to put java in /usr/lib or /usr/share or something like that.

P.S.
With the Sun JRE, you don't normally need to set JAVA_HOME or CLASSPATH at all.

[akhilanger]

If you have installed java through sudo apt-get install ......
then it is installed in /usr/lib/jvm

[bwakkie]

euhm.. is my case:

which java
/usr/bin/java

ls -l /usr/bin/java
/usr/bin/java -> /etc/alternatives/java

ls -l /etc/alternatives/java
/etc/alternatives/java -> /usr/lib/jvm/java-gcj/jre/bin/java

Changed that to:
java -> /usr/lib/jvm/java-6-sun-1.6.0.06/jre/bin/java


then I added the following line to /etv/environment:
JAVA_HOME="/usr/lib/jvm/java-6-sun-1.6.0.06/"

and created the following symlink:
/usr/java/jdk -> /usr/lib/jvm/java-6-sun-1.6.0.06/

although I have both... java is sooooo confusing!!

[elnur]

Originally Posted by bwakkie Changed that to: java -> /usr/lib/jvm/java-6-sun-1.6.0.06/jre/bin/java and created the following symlink: /usr/java/jdk -> /usr/lib/jvm/java-6-sun-1.6.0.06/

You really shouldn't. Just run this command:

sudo update-java-alternatives -s java-6-sun

It will set java-6-sun to be run by default.

[Juzz]

Originally Posted by elnur You really shouldn't. Just run this command: sudo update-java-alternatives -s java-6-sun It will set java-6-sun to be run by default.

Why does java on linux have to be so obscure?

I was wondering why my netbank didn't work anymore - but when I ran java --version gcj had stolen my settings from sun being default...

Even after running that command to set java alternatives firefox hangs and uses up 100% cpu time when trying to access my netbank