Java Method Overloading
In Java, it is possible for a class to contain two or more methods with the same name but with different parameters. Such methods are called Overloaded methods.
Method overloading is used to increase the readability of the program.
void foo()
void foo(int a) //Overloaded function foo
int foo(int a, int b)
Ways to perform method overloading :
In Java, method overloading can be performed by two ways listed below :
1. By changing the return type of the different methods
2. By changing the number of arguments accepted by the method
Now, let's have an example to understand the above ways of method overloading :
By changing the return type :
In the below example, we've created a class named calculate. In the calculate class, we've two methods with the same name i.e. multiply These two methods are overloaded because they have the same name but their return is different. The return type of 1st method is int while the return type of the other method is double.class calculate{
int multiply(int a,int b){
return a*b;
}
double multiply(double a,double b){
return a*b;
}
public static void main(String[] args) {
calculate obj = new calculate();
int c = obj.multiply(5,4);
double d = obj.multiply(5.1,4.2);
System.out.println("Mutiply method : returns integer : " + c);
System.out.println("Mutiply method : returns double : " + d);
}
}
Output
Mutiply method : returns integer : 20
Mutiply method : returns double : 21.419999999999998
Mutiply method : returns double : 21.419999999999998
By changing the number of arguments passed :
Again, we've created two methods with the same name i.e., multiply. The return type of both the methods is int. But, the first method 2 arguments and the other method accepts 3 arguments.
Example :
class calculate{
int multiply(int a,int b){
return a*b;
}
int multiply(int a,int b,int c){
return a*b*c;
}
public static void main(String[] args) {
calculate obj = new calculate();
int c = obj.multiply(5,4);
int d = obj.multiply(5,4,3);
System.out.println(c);
System.out.println(d);
}
}
Output
20
60
60
Note: Method overloading cannot be performed by changing the return type of methods.Example
package com.company;
public class method_overloading {
static void foo(){
System.out.println("Good Morning bro!");
}
static void foo(int a){
System.out.println("Good morning " + a + " bro!");
}
static void foo(int a, int b){
System.out.println("Good morning " + a + " bro!");
System.out.println("Good morning " + b + " bro!");
}
static void foo(int a, int b, int c){
System.out.println("Good morning " + a + " bro!");
System.out.println("Good morning " + b + " bro!");
}
static void change(int a){
a = 98;
}
public static void main(String[] args) {
// Method Overloading
foo();
foo(3000);
foo(3000, 4000);
// Arguments are actual!
}
}
Output
Good Morning bro!
Good morning 3000 bro!
Good morning 3000 bro!
Good morning 4000 bro!
Good morning 3000 bro!
Good morning 3000 bro!
Good morning 4000 bro!