Mar 28, 2025 · The interface in Java is a mechanism to achieve abstraction. By default, variables in an interface are public, static, and final. It is used to achieve abstraction and multiple inheritance in Java. It supports loose coupling (classes depend on behavior, not implementation).

Another way to achieve abstraction in Java, is with interfaces. An interface is a completely " abstract class " that is used to group related methods with empty bodies: To access the interface methods, the interface must be "implemented" (kinda like inherited) by another class with the implements keyword (instead of extends).

We use the interface keyword to create an interface in Java. For example, public void getType(); public void getVersion(); Here, Language is an interface. It includes abstract methods: getType() and getVersion(). Like abstract classes, we cannot create objects of interfaces. To use an interface, other classes must implement it.

Mar 14, 2023 · In Java, an interface is a reference type similar to a class that can contain only constants, the method signatures, default methods, and static methods, and its Nested types. In interfaces, method bodies exist only for default methods and static methods. Writing an interface is similar to writing to a standard class.

Apr 5, 2025 · An interface in Java is a blueprint of a class. It has static constants and abstract methods. The interface in Java is a mechanism to achieve abstraction. There can be only abstract methods in the Java interface, not a method body. It is used to achieve abstraction and multiple inheritance in Java.

Jun 11, 2024 · In this tutorial, we’re going to talk about interfaces in Java. We’ll also see how Java uses them to implement polymorphism and multiple inheritances. 2. What Are Interfaces in Java? In Java, an interface is an abstract type that contains a collection of …

Learn about Java interfaces, their purpose, and how to implement them effectively in your Java applications. Explore examples and best practices. Explore the fundamentals of Java interfaces, including their purpose and implementation methods.

Feb 1, 2020 · Interface in Java is a bit like the Class, but with a significant difference: an interface can only have method signatures, fields and default methods. Since Java 8, you can also create default methods. In the next block you can see an example of interface: The interface above contains two fields, two methods, and a default method.

Sep 26, 2019 · Simply put, an interface is a collection of methods with empty bodies. Let’s take a look at the Runnable interface in the java.lang package: This interface declares the run () method which is empty (ends with a semicolon).

In this article from my free Java 8 course, I will explain the topic of interfaces in Java. Interface is a generic term that is used widely across fields. Wiktionary defines it as “The point of interconnection between entities”. This term has been adapted to programming and plays a key role in Object Oriented Programming (OOP).