I did these steps without error:

   1-JDK path : Downloads/jdk-6u37-linux-x64.bin

   2-Commands in Terminal  :
               mkdir Programs
               cd Programs
               bash ../Downloads/jdk-6u37-linux-x64.bin
               ln -s jdk-6u37-linux-x64 jdk

    3-Set JAVA_HOME and  Path:
               in Home>View Menu>Show Hidden Files
               Then open .bashrc in text editor.
               I added the following lines to end of file.      

                             export JAVA_HOME=$Home/Programs/jdk
                             export PATH=:$JAVA_HOME/bin:$PATH
---------------------------------------------------------------------------------------
This is the result of executing the command echo $JAVA_HOME :

/Programs/jdk

This is the result of executing the command echo $PATH :

:/Programs/jdk/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games1
----------------------------------------------------------------------------------------
And problem is :
This is the result of executing the command  java -version :

The program 'java' can be found in the following packages:
 * default-jre
 * gcj-4.6-jre-headless
 * gcj-4.7-jre-headless
 * openjdk-7-jre-headless
 * openjdk-6-jre-headless
Try: sudo apt-get install