Content Summary : The current version of Java (J2SE 5.0) provides a high level of support for concurreny in comparison to previousversions. For example, programmers using J2SE 5.0 cannow achieve synchronization between concurrent threadsusing explicit locks, semaphores, barriers, latches, or ex-changers. Furthermore, built-in concurrent data structuressuch as hash maps and queues, built-in thread pools, andatomic variables are all at the programmer’s disposal. We are interested in using mutation analysis to evalu- ate, compare and improve quality assurance techniques forconcurrent Java programs. Furthermore, we believe thatthe current set of method mutation operators and class op-erators proposed in the literature are insufficient to evaluateconcurrent Java source code because the majority of oper-ators do not directly mutate the portions of code responsi-ble for synchronization. In this paper we will provide anoverview of concurrency constructs in J2SE 5.0 and a newset of concurrent mutation operators. We will justify the op-erators by categorizing them with an existing bug patterntaxonomy for concurrency. Most of the bug patterns in thetaxonomy have been used to classify real bugs in a bench-mark of concurrent Java applications.