java file will not launch from .desktop file - Ubuntu 12.04 LTS

I have a bin/bash script-

 #!/bin/bash

 java -Xms256m -Xmx1g -jar KeeperDesktop.jar

inside an executable text file ( keeper-start)

I have created a .desktop file for it as i want to launch it from Unity Launcher

[Desktop Entry]
Name=Keeper
Type=Application
Exec=java -Xms256m -Xmx1g -jar KeeperDesktop.jar
Terminal=false
Icon=/home/dt/keeper/keeper.jpg
Comment=KeeperSecurity Datavault
NoDisplay=false
Categories=Applications
Name[en]=keeper.desktop

I have the icon in the Launcher but the app won't start

This is the limit of my knowledge that I have gleaned from other answers on this site , I am hoping someone can help me finish this process

thanks David