Learn the difference between classes and interfaces once and for all, then get started declaring, implementing, and extending interfaces in your Java programs ...

Learn how to create and use an interface in C, which is a way of defining a set of functions that a struct must implement to achieve polymorphism.

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.

How does the open-closed SOLID principle work in a Java program? Here we show you what this important principle means, and how to implement the open-closed principle in Java.

The functional consumer interface is a key part of the Java Streams API. Here is a simple Consumer interface example to show you how to use this Java component.

Learn how to create and use an interface in C, which is a way of defining a set of functions that a struct must implement to achieve polymorphism.