Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.

In this Java 101 tutorial, I’ve explained how interfaces differ from classes, and showed you how to declare, implement, and extend interfaces in your Java programs.

A public method should never be called by another public method within the same class hierarchy. It should only be called by other classes via the classes' public interface. Class calls might not be ...

Also known as the Java 8 Predicate -- which stems from the JDK version where functional programming was introduced to developers -- this simple interface defines five methods, although only the Java ...