Java: An Introduction to Problem Solving and Programming, 8th Edition

Chapter Summary

• A Java interface contains the headings of public methods and the definitions of public named constants. It does not declare constructors or private instance variables.

• A class that implements an interface must define a body for every method that the interface specifies. It might also define methods not declared in the interface. A class can implement more than one interface.

• An interface provides a way for a class designer to specify methods for another programmer. By implementing an interface, a programmer can guarantee that a class defines certain methods.

• An interface is a reference type, and so you can declare variables and method parameters as having an interface type.

• You can extend an interface to create an interface that ...