Java doesn't have unsigned integer types (except byte IIRC), so signed long is your only option. OTOH the bitwise ops are specced to operate as if they operated on twos complement represented signed integers, so you can at least do that kind of stuff if you need to, on the full 64 bits.
>
> isThisPossible(t1 < 0);
> 5) No, it's not possible, at least something is not possible
Well, maybe not any time soon, but eventually (in Java at least) that will wrap around and therefor it's possible.