This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
Typically, all double no matter their size are *stored* in scientific notation (okay, actually it's a variation that is given by some IEEE standard). I suspect you are worried more about how the double is *displayed* instead. You should be able to get some control over this by using NumberFormat. Take a look at the API docs (follow the link) for more information.