Interfaces , Exercises


Show that variables in an interface are implicitly public, static, and final.


Create an interface with three methods getA(), getB(), and getC() in a package. Implement the interface in a class in a different package.


Show that all methods in an interface are automatically public.


Create three interfaces each with a single method. Create a new (fourth) interface that inherits from the three first interfaces and that adds a single method. Create a new class that both implements the new interface and inherits from another class. In the new class, write four methods that each takes a single formal argument of the interface type created. Create an object of the new class in a main method and show that this object can be given as argument to the four methods defined on the class.

Extra Assignments


Use the four interfaces from Exercise D. Create a new abstract class that implements all these interfaces but does now provide a method body for one of the methods defined in an interface. Create another concrete class that inherits from the abstract class.