Problem is if i double click it executing both the single then double. Why would this be happening?
Yes, because thats the way applications are normally designed.
a) a single click selects the item
b) a double click performs some action on the item
And that is why you can also use the keyboard:
a) the arrow keys are used to select an item
b) the Enter key would then typically before an action on the item (although for a JTable the default is to just move to the next row you can always write a custom Action).
Since both have tasks that read same file
Sounds to me like a bad design. Remember what I suggested above. Whatever you can do with the mouse you should be able to do with the keyboard. So it does not make sense to read a file every time you use an arrow key.
But, strangely enough you are not the first person to ask for something like this and I happen to have some old code lying around: