A common source of threading issues is the usual approaches employed to synchronize data. Having threads share state and then implement locking at all the appropriate places is a major source of complexity for both design and debugging. Getting the locking right to balance stability, performance, and scalability is always a hard problem to solve. Even the most experienced experts get it wrong frequently. Alternative techniques to deal with threading can alleviate much of this complexity. The Clojure programming language implements several interesting techniques for dealing with concurrency.
