Cliff Click's presentation of his lock-free hash table is interesting in this respect. He used a different approach - based on state machines - for reasoning about correctness:<p><a href="http://video.google.com/videoplay?docid=2139967204534450862#" rel="nofollow">http://video.google.com/videoplay?docid=2139967204534450862#</a><p>(Cliff Click was architect and lead developer for the HotSpot server JIT compiler.)