x. Briefly describe the difference between a class method and an instance method. xi. In the statement System.out.println("hello, world!");, explain what System xii. Briefly describe the difference between the stack and the heap in our memory model. xii. Briefly describe the four sections of the memory model discussed in class: stack, heap, out and println each are. data segment, code segment. xiv. What is "this" in Java? xv. Briefly describe the two uses of this in a constructor. xvi. Briefly describe what an activation record is and what it is used for. xvii. Java provides eight primitive wrapper classes. Explain what they are. xvii. Strings are immutable in Java. What does this mean? xix. Can a Java class have no constructors? (Explain yes or no.) xx, Given String s = new String("cat"); and String t = "cat"., draw the box & arrow diagram for these two variables