Mutators are public methods that are used to modify the state of an object, while hiding the implementation of exactly how the data gets modified.
Mutators are commonly another portion of the property discussed above, except this time it is the set method that lets the caller modify the member
data behind the scenes. By hiding the implementation for example Person class, we can make changes to the Person class without the worry that we are
going to break other code that is using and calling the Person class for information. If we wanted, we could change the middleName from a String to an
array of single characters but their callers would never have to know because we would still return them a single middleName string, but behind the scenes
we are dealing with a character array instead of a string object. It’s transparent to the rest of the program. This type of data protection and implementation
protection is called Encapsulation. Think of accessors and mutators as the pieces that surround the data that forms the class.