Not sure it's quite what you're looking for, but check out the colt
It has some classes for manipulating BitVectors.
"Wilson, Andrew, J" wrote:
> I need to convert some IBM formatted floating point data from
> a binary file so I can read into VisAd. This uses a different
> number of bits for the exponent and mantissa than is used by
> the IEEE representation. Can anyone point me at code or a
> tutorial on bit-twiddling in Java?