Java Method Overloading Explained with Code Samples

Java method overloading allows defining two or more methods within the same class that share the same name. Method overloading makes the code clean and increases the readability of the code. Method overloading helps to achieve polymorphism which is one of the object oriented principles.  In this article, I will be covering method overloading in detail.

Introduction

When methods are overloaded, their parameter declarations need to be different. The following code demonstrates this:

public class AdditionService {             int add() { // no parameters             return 3+5;       }             int add(int i) { //one integer parameter             return i+i;       }             int add(int i,int j) { //two integer parameters             return i+j;       }             double add(double i,double j) { //two double parameters             return i+j;       }            }

This class has 4 methods with the name add. All four add methods differ in the parameters, so there is no compilation error.  So the add method is said to be “overloaded” four times.

The following code invokes these methods:

       public static void main(String[] args) {             AdditionService as = new AdditionService();                         int sum1 = as.add();             System.out.println("Sum1 is "+sum1);                         int sum2 = as.add(5);             System.out.println("Sum2 is "+sum2);                         int sum3 = as.add(10,20);             System.out.println("Sum3 is "+sum3);                         double sum4 = as.add(4.5, 6.7);             System.out.println("Sum4 is "+sum4);       }

 

This code prints the following output:

Sum1 is 8Sum2 is 10Sum3 is 30Sum4 is 11.2

Overloading using Return Types

Overloaded methods must differ in the type and/or number of their parameters. So if the type/number of arguments is the same but return types are different, then the methods are not overloaded and the code will cause a compilation error. The following code demonstrates this:

public class AdditionService {//this code causes a compilation error       int add(int i,int j) {             return i+j;       }             double add(int i,int j) {             return i+j;       }}

Here, both the add methods accept two integer arguments. However the first method returns an integer while the second methods returns a double value.  This code causes a compilation error because there are two add methods accept 2 integer

 

How method overloading works

When an overloaded method is invoked, Java uses the type and/or number of arguments to determine which version of the overloaded method to actually call. So Java simply executes the version of the method whose parameters match the arguments used in the call. While overloaded methods may have different return types, the return type alone is insufficient to distinguish two versions of a method. So if two methods have exactly the same number and type of parameters, but different return types, there will be a compilation error. Method overloading is one of the ways that Java supports the object-oriented principle of polymorphism.

Conclusion

So in this article, we saw how method overloading works in Java.

Comments

Post a Comment

Popular posts from this blog

How to use logging in SpringBoot with code samples

Image
In this article, we will learn how to use logging in SpringBoot. Introduction There are several Java logging frameworks like logback, log4j, and so on. Spring Boot supports out-of-the-box support for logback. Let us learn how to use logging in SpringBoot with logback. Step 1 – Create a New Maven Project Create a new Maven project. (Refer to  this  blog post). This will create a project in Eclipse as follows:   Step 2 – Add the Spring Boot Dependencies Add the spring-boot-starter-web dependency to the pom.xml . So, the pom.xml should look as follows: <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.learnjava</groupId> <artifactId>learnjava-springboot-logging-example</artifactId> <version>0.0.1-SNAPSHOT&
Read more

Python While Loop with code samples

Much like a Java while loop, you can use a Python while loop to repeatedly execute a block of code as long as a condition is true. In this article, we will learn more about the Python while loop. Python While loop Syntax A while loop in Python has the following syntax: while <condition>: loop body The while keyword is followed by a condition. If the condition evaluates to true, the body of the loop is executed. Once the body of the loop is completed, the condition is checked again and this is repeated until the condition evaluates to false at which point the loop is exited. While loop Sample Code The following code demonstrates how you can use the while loop: num=10counter=1total=0while counter<=num: total += counter counter+=1print("sum of first 10 numbers is",total) This code adds the numbers from 1 to 10 and prints the sum. It uses a while loop to iterate from 1 to 10. The while loop checks the condition counter <= num and if so adds the current value of count
Read more

How to convert a List to a Set

In this blog post ,I will be showing you how you can convert a List to a Set. Consider the following code snippet: public class ListToSetDemo {public static void main(String[] args) {List<Integer> list = Arrays.asList(5,3,11,15,9);//Method 1Set<Integer> set = new HashSet<Integer>(list);System.out.println("Set is "+set);//method 2Set<Integer> set2 = new HashSet<Integer>();set2.addAll(list);System.out.println("Set is "+set2);}} This code demonstrates two ways to convert a List to a Set. Method 1 Here, we are creating a new HashSet . We are invoking the constructor that accepts a Collection object. Here, we are passing in the input list to this constructor.   Method 2 Here again, we are creating a new HashSet . However, we are using the default constructor. We are then invoking the addAll method and passing in the input list.   When you run this code, it will print the following output: Set is [3, 5, 9, 11, 15]Set is [3, 5, 9, 11, 15] No
Read more