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.

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 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.