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Overriding vs Overloading in Java

Published on August 3, 2022 · Updated on September 30, 2022
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By Pankaj
Developer and author at DigitalOcean.
Overriding vs Overloading in Java

Introduction

Overriding and overloading are the core concepts in Java programming. They are the ways to implement polymorphism in our Java programs. Polymorphism is one of the OOPS Concepts.

Overriding versus overloading in Java
Screenshot of Java code with arrows pointing at instances where overloading and overriding are occurring.

When the method signature (name and parameters) are the same in the superclass and the child class, it’s called overriding. When two or more methods in the same class have the same name but different parameters, it’s called overloading.

Comparing overriding and overloading

Overriding Overloading
Implements “runtime polymorphism” Implements “compile time polymorphism”
The method call is determined at runtime based on the object type The method call is determined at compile time
Occurs between superclass and subclass Occurs between the methods in the same class
Have the same signature (name and method arguments) Have the same name, but the parameters are different
On error, the effect will be visible at runtime On error, it can be caught at compile time

Overriding and overloading example

Here is an example of overloading and overriding in a Java program:

package com.journaldev.examples;

import java.util.Arrays;

public class Processor {

	public void process(int i, int j) {
		System.out.printf("Processing two integers:%d, %d", i, j);
	}

	public void process(int[] ints) {
		System.out.println("Adding integer array:" + Arrays.toString(ints));
	}

	public void process(Object[] objs) {
		System.out.println("Adding integer array:" + Arrays.toString(objs));
	}
}

class MathProcessor extends Processor {

	@Override
	public void process(int i, int j) {
		System.out.println("Sum of integers is " + (i + j));
	}

	@Override
	public void process(int[] ints) {
		int sum = 0;
		for (int i : ints) {
			sum += i;
		}
		System.out.println("Sum of integer array elements is " + sum);
	}

}

Overriding

The process() method and int i, int j parameters in Processor are overridden in the child class MathProcessor. Line 7 and line 23:

public class Processor {

    public void process(int i, int j) { /* ... */ }

}

/* ... */

class MathProcessor extends Processor {
 
    @Override
    public void process(int i, int j) {  /* ... */ }

}

And process() method and int[] ints in Processor are also overridden in the child class. Line 11 and line 28:

public class Processor {

    public void process(int[] ints) { /* ... */ }

}

/* ... */

class MathProcessor extends Processor {

    @Override
    public void process(Object[] objs) { /* ... */ }

}

Overloading

The process() method is overloaded in the Processor class. Lines 7, 11, and 15:

public class Processor {

    public void process(int i, int j) { /* ... */ }

    public void process(int[] ints) { /* ... */ }

    public void process(Object[] objs) { /* ... */ }

}

Conclusion

In this article, we covered overriding and overloading in Java. Overriding occurs when the method signature is the same in the superclass and the child class. Overloading occurs when two or more methods in the same class have the same name but different parameters.

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About the authors
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Pankaj

author

Developer and author at DigitalOcean.

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JournalDev
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February 3, 2022

Thanks you. because l have irritating this concept understanding after that your implement concept and explain easy understanding ,so iam very happy

- ambika

    JournalDev
    DigitalOcean Employee
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    January 31, 2022

    Its good but with an Example its better for more Understanding. Overall efforts are good.

    - Shriganesh Mane

      JournalDev
      DigitalOcean Employee
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      September 10, 2021

      Great explanation of the topic. You made it simple and easy to understanding. Thank you.

      - David

        JournalDev
        DigitalOcean Employee
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        June 9, 2021

        Nice, concise explanations. Referring my students here for this topic.

        - Mark Miller

          JournalDev
          DigitalOcean Employee
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          May 21, 2021

          thanks for clear explanation of difference

          - MOHAMMAD AHTISHAM

            JournalDev
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            August 24, 2019

            hello, very happy with this website.

            - ranjit vamadevan

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