This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
You cannot use this inside a static block because this relates to an instance of a class ("this instance"), while static blocks belong to the class itself. So, which one is the this instance when you're inside a block that does not belong specifically to any instance? In the case of your program, the static block is execute when the class is loaded, that's why the first output you see is "Static block started". Then, instace data is initialized. Is that clear?