If you have not used Google’s Java Collection library (now known as Guava) I highly recommend it. Particularly its Iterators util class.

Iterators.partition is extremely useful. Unfortuanatly they don’t have an Iterators.flatten (easy to write but I was hoping they would have it).

Hopefully  they’ll add it soon.

http://code.google.com/p/guava-libraries/issues/detail?id=627

Now if Java only had better syntactic sugar like F# or Haskell does for piping iterators/sequences.