If the exercise alraeady gives out TRUE when run, what is the point of the static block and the synchronized block?

Usually you use the constructor two initialize class variables. As you know, a static variable is used from all instances together, so it may not always be intended to change it from a single instance. Therefore you have the static block, to initialize static variables. It's run only once during class loading. The second problem is, that the constructor is private. So that one can't get used for class/ instance variable initialization. So you can do it here with static variables the same way as with instance variables. Either use direct initialization or use the constructor/ static block. The synchronization... that one is more difficult. To my understanding (I did some reading every now and then on how to initialize singletons) the class loader synchronizes the static block by definition (invisible for us - check the JVM specification for more technical info). So it is not necessary to synchronize the static explicitly. Later you'll learn about lazy initialization (other ways to create a singleton), then synchronization is necessary again (until you again learn more ways to instanziate it). Here both, the synchroniation and the static block are necessary cause of task requirements.