[Java] Method Overloading

 Method Overloading

If a class have multiple methods by same name but different parameters, it is known as Method Overloading

1. Advantage of method overloading

- Method overloading increases the readability of the program

2. Different ways to overloading the method

2_1. By changing number of arguments

2_2. By changing the data type

1) By changing the number of arguments

package overloading; import static org.hamcrest.CoreMatchers.is; import static org.junit.Assert.assertThat; import org.junit.Test; import org.junit.runner.JUnitCore; public class Overloading { public static void main(String[] args){ JUnitCore.main("Array.ArrayConvert"); } int sum(int a, int b){ return a + b; } int sum(int a, int b, int c){ return a+b+c; } @Test public void byNum(){ Overloading test = new Overloading(); assertThat(test.sum(10,10,10),is(30)); assertThat(test.sum(10,10),is(20)); } }

2) By changing the data type

package overloading; public class Overloading { public static void main(String[] args){ Overloading test = new Overloading(); test.sum(10, 10); test.sum(10, 10,10); } void sum(int a, int b){ System.out.println(a+b); } void sum(double a, double b, double c){ System.out.println(a+b+c); } }  

3. Questions

3_1. Why method overloading is not possible by changing the return type of method?

- there may occur ambiguity.

3_2. Can we overloading main() method?

 public class Overloading { public static void main(int a){ System.out.println(a); } public static void main(String args[]){ System.out.println("main() method invoked"); main(10); } }  

- Yes