[ Environment Variable ] Probleme with export JAVA_HOME

Hi,

I want to create a new environment variable (JAVA_HOME), but when I open a new shell this varible is delete...
to create the variable I do :

export JAVA_HOME=/usr/java/jdk

and I verify with :

echo $JAVA_HOME

and it's work...
But When I open a new shell this variable is forget...
( It does the same thing with PATH...)

Do you know why it does this?? And how to fix it?

Rem : I have ever done this way to change my variable PATH and it has worked...

Put it in "$HOME/.profile" or whatever similar file your system uses.

I've changed the file : /etc/profile
(the change will be apply for all the users)