This tutorial introduces the difference between classes and interfaces, then guides you through examples demonstrating how to declare, implement, and extend Java interfaces.

Create packages, import packaged classes and interfaces into your programs, move packages, and encapsulate them in jar files.

Applying the open-closed principle in Java The addition of an interface to our example helps to overcome the violation of the open-closed principle. An interface allows for infinite future extensions ...

Functional supplier interface in Java tutorial There are only half a dozen classes you really need to master to become competent in the world of functional programming. The java.util.function package ...

If you want to take advantage of sorting methods in Java, you'll need to implement the Comparable interface.