Importance of @Override annotation in Java?

What is an Annotation?

An annotation is like metadata that provides additional information about the code. It does not affect the code directly but provides the information so that the compiler or runtime environment can use it while executing the code.

To define or use any annotation in Java, you need to specify the annotation name starting with the "@" symbol. Here is the syntax to use annotations in Java:

@annotation_name

Where the @ symbol specifies the annotation, and annotation_name is the name of the annotation. Following is a list of a few important annotations and their usage:

@Override Annotation in Java

In Java, the @Override annotation is one of the default Java annotations, and it was introduced in Java 1.5. The @Override annotation indicates that the child class (or derived class) method overrides its base class (parent class) method.

In addition, the @Override annotation informs the compiler that the element is meant to override an element or method declared in a superclass. If a method is marked with the @Override annotation and fails to override the method correctly, then the compiler will generate an error.

Syntax

Following is the syntax of the @Override annotation:

@Override
method_name() {
   // method body
}

Where the method_name is the method of your base class that you want to override in the child class.

Example

In the following example, the child class overrides its parent (super) class method using the @Override annotation:

// Parent class
class BaseClass {
   public void display() {
      System.out.println("In the base class, display() method");
   }
}

// Child class extends parent using inheritance
class ChildClass extends BaseClass {
   // Using @Override annotation to override the parent method
   @Override 
   public void display() {
      System.out.println("In the child class, display() method");
   }
}

public class OverrideAnnotationTest {
   public static void main(String[] args) {
      System.out.println("Java @Override Annotation Example");
      
      // Reference of parent class pointing to object of child class
      BaseClass test = new ChildClass();
      // Calling the overridden method in ChildClass
      test.display(); 
   }
}

The above program produces the following output:

Java @Override Annotation Example
In the child class, display() method

Importance of the @Override Annotation

Here are a few important points of the @override annotation in Java:

• It is used to override the parent method.
• It detects an error at compile time if the annotated method doesn't override anything or incorrectly override the method.
• It improved the code readability so that anyone can understand the method override from its parent class.