Each week we provide some exercises for you to practice concurrent programming, get to know Java and Erlang in order to prepare yourselves for the assignments. None of the exercises are mandatory.
The goal of most of the exercises is to allow you to practice some of the material from the lectures, and allow you to prepare for the assignments. Some of the exercises give you a direct head start for certain assignments.
The solutions to all of the exercises are available online from the start of the course. Do make an effort to solve them yourself before looking at the solutions, however. Solving the exercises yourself will help you learn the concepts covered in the course, which will obviously help you quite a bit when the exam rolls around.