created 12/13/98; revised: 09/23/99, 01/21/00, 07/14/02, 01/19/06, 11/11/08, 07/31/14
So far, the objects that we have designed have instance variables that are visible outside of the objects. Code that holds a reference to an object can change the object's instance variables. This can lead to problems.
A better design enforces encapsulation, where
an object's instance variables are
visible only to the object's own methods.
Code outside of the object cannot directly access these variables.
This chapter discusses how to use the
private visibility modifier
to do this.
Should a bank control who has access to your checking account?