The java.util.concurrent approach also introduced the ability to set time units explicitly rather than specifying everything in number of milliseconds. This is available via the TimeUnit enum.

Writing correct concurrent programs is harder than writing sequential ones. This is because the set of potential risks and failure modes is larger - anything that can go wrong in a sequential program ...

If your standby garbage collector option, Concurrent Mark Sweep, won't work on future Java releases, here are some option to consider as an alternative.

Parallelism is achieved by using #pragma parallel in openmp, using message passing in MPI and by using threads in concurrent java.