The intersection of two collections is a new collection of the entries that occur in both collections. That is, it contains the overlapping entries. Define a method intersection for the class...

The intersection of two collections is a new collection of the entries that occur in both collections. That is, it contains the overlapping entries. Define a method intersection for the class BagOfStrings that returns as a new bag the intersection of the bag receiving the call to the method and the bag that is the method’s one argument. Note that the intersection of two bags might contain duplicate items. For example, if object x occurs five times in one bag and twice in another, the intersection of these bags contains x twice. Specifically, suppose that bag1 and bag2 are BagOfStrings objects; bag1 contains the String objects a, b, and c; and bag2 contains the String objects b, b, d, and e. After the statement

BagOfStrings commonItems = bag1.intersection(bag2); executes, the bag commonItems contains only the string b. If b had occurred in bag1 twice, commonItems would have contained two occurrences of b, since bag2 also contains two occurrences of b. Note that intersection does not affect the contents of bag1 and bag2.