Related to fork/join framework, you will find the following exam topic under concurrency at oracle site: Use the parallel Fork/Join Framework
So, yes, the exam covers this topic. We have seen questions mainly on usage of methods belonging to ForkJoinTask and ForkJoinPool classes and placement of methods such as fork() and join().
In our book, we explained what is fork/join framework, why it is useful, what are the important methods of ForkJoinTask and ForkJoinPool classes, and how you can use it effectively (using an example). Finally, we presents interesting points about the framework.