Java ClassesLesson 39Free preview

Java Interface

This lesson is part of Java · All levels

Summary

The interface defines a contract as a method that must be implemented by the user class. One class can implement multiple interfaces at once, thus overcoming the limitations of single inheritance in Java. Since Java 8, the interface can also have a default method already contained.

Key points

Interface declared with keyword interface, implemented with implementations
Traditionally, the method interface has only a signature without a body.
A class can implement more than one interface
Interfaces are often used to define the capabilities of many different types.

Full lesson

Code examples and quizzes

Full lessons, code examples, and quizzes are available to subscribers. 5 questions.