After calling GridFSDownloadStreamImpl.skip() with a value larger than 2GB, e.g. 2306734080, the subsequent read() fails with ArrayIndexOutOfBoundsException.

It seems like this casting is missing some parentheses at line 117:

        bufferOffset = (int) skippedPosition % chunkSizeInBytes;

This is in effect:

        bufferOffset = ((int) skippedPosition) % chunkSizeInBytes;

But should have been:

        bufferOffset = (int) skippedPosition % chunkSizeInBytes;

The same applies here at line 126:

Math.floor((float) skippedPosition / chunkSizeInBytes)

(Why float by the way, and not double?)