The interface java.util.Iterator contains an additional method remove(). What does this method do and explain any difficulties that you for see if this is implemented.

We have already noted that the singleton pattern can be realized by having a class that contains nothing but a set of static methods. Find a real-life example of a singleton class and show that this observation is true. Next, identify a pair of classes in which one is a subclass of the other and both are singletons. Attempt to use the static methods approach to make them singletons and convince yourself of the difficulties.

Compare and contrast the interfaces Enumeration and Iterator in java.util.