Multithreaded execution where order of finished Work Items is preserved

Question

I have a flow of units of work, lets call them \"Work Items\" that are processed sequentially (for now). I\'d like to speed up processing by doing the work multithreaded.

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Answer 1

If you allow BlockingQueue, why would you ignore the rest of the concurrency utils in java? You could use e.g. Stream (if you have java 1.8) for the above:

List data = ...;
List out = data.parallelStream()
    .map(t -> doSomeWork(t))
    .collect(Collectors.toList());

Because you started from an ordered Collection (List), and collect also to a List, you will have results in the same order as the input.