Refactoring Sequential Java Code for Concurrency via Concurrent Libraries

This paper presents a way for restructuring sequential code into parallel code using concurrent utilities. It makes use of the java.util.concurrent framework in Java5 and the ForkJoinTask Framework in Java7. I liked the argument that programming with locks in error-prone. Though I believe this is a contentious topic, I tend to agree with the authors' comments on this. The frameworks mentioned in the paper have addressed the research issues of usefulness, of making the existing code thread-safe, and finally of efficiency. The evaluation methodology used by concurrencer is pretty much comprehensive, and I doubt that many questions could be raised about this.

In the implementation, I liked the concept of ConcurrentHashMap , which avoids locking of the entire map.The number of ways in which refactoring is supported is pretty impressive and allows for parallelizing of different kinds of sequential code patterns. Another important aspect of this paper is that they have accounted for human intervention while retrofitting parallelism into sequential code. In this way, I believe they have accounted for future changes in code (especially if drastic changes have to be made in the code). It is also interesting to note that among the three conversions studied in this paper, only ConcurrentHashMap requires a degree of human intervention.