Question

Could somebody please provide an example where getters and setters are not required?

I still do not get the idea, I guess a very huge class with lots of attributes must have them but in simpler cases?

Answer 1

Getters and setters have a number of related purposes:

• They abstract the state of the class. Generally speaking, it is a good thing to hide implementation details.
• They make it easier for the implementor to change the attribute’s representation type.
• They make it possible to override aspects in child classes. (An exposed attribute cannot be overridden.)
• They allow the class to control access and update. For example, a setter can stop some client code from setting an attribute to a “wrong” value.
• They allow a class to be used as a Java Bean.

All of these add up to a convincing argument for using setters and getters everywhere.

To my mind, there is only two cases where getters and setters are “optional”:

• When the attributes are only ever used by the class itself; i.e. they are private.
• When the attributes belong to a light-weight private inner class; i.e a class whose instances will only ever exist and be visible within the encapsulation boundary of the outer class.

In these cases, the reasons for using getter and setters mostly don’t apply. In particular, since the visibility of the attributes and their types are restricted to the enclosing class, the ripple effect of changing them is limited to the source code file that defines the class.

However, if there is a risk that the inner classes implementation details will leak in a revision of the code, you should immediately add getters and setters.