Question: Create a subclass of Default Builder that always returns null except when it is asked to build a Class Declaration node, in which case, it still returns null, but it also keeps track of the number of times it was asked to create such a node. It should also have a method with the following header:
public int number of Class Declarations () that returns the number of class declarations the builder counted during the parsing of a program and a method with header
public void reset()
that resets to 0 the number of class declarations the builder found.