Store/protocol APIs have gradually been evolving to accept/return message content/message metadata in terms of an ordered list of QBBs. This has lead to use of helper methods such as those in QBBUtils which read from a list of buffers rather than a single one.
This would be better refactored. QpidByteBuffer should be an interface. This would allow a concrete implementation CompositeQpidByteBuffer which is backed by a list produced by the store or network IO.