Java Circuit

In addition to overloading normal methods, we can also overload constructors. In fact, for most real-world classes that you create, overloaded constructors will be the norm.

Have a look at the fallowing example

Example I

// Demonstartion of Constructor Overloading

/**
 *
 * @author Sudarsan
 */
class Sample {

    int i,j,k;

    //Constructor with three Parameters
    public Sample(int i,int j,int k)
    {
        this.i=i;
        this.j=j;
        this.k=k;

        System.out.println("Values of I, J and K :"+i+" "+j+" "+k);
    }
    //Constructor with two parameters
    public Sample(int i,int j)
    {
        this.i=i;
        this.j=j;
        System.out.println("Values of I, J :"+i+" "+j);
        
    }
    //Constructor with only one Parameter
    public Sample(int k)
    {
        this.k=k;
        System.out.println("Value of K :"+k);
    }
}

// Constructing three different Object for the Class Sample
/**
 *
 * @author Sudarsan
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here

        Sample s1=new Sample(10,20,30);

        Sample s2=new Sample(10,20);
        
        Sample s3=new Sample(10);
    }

}

When we compile this program we can see the fallowing output

Values of I, J and K :10 20 30
Values of I, J :10 20
Value of K :10

THIS Constructor

Have a look at the fallowing example to use THIS CONSTRUCTOR

// Using THIS Constructor
/**
 *
 * @author Sudarsan
 */
 class Employee {
    
    private String dept;
    private String name;
    private double salary=20000.00;
    
    public Employee(String name,double salary,String dept )
    {
       this.name=name;
       this.salary=salary;
       this.dept=dept;
        
    }

    public Employee(String name,double salary)
    {
        // Passing values to the above constructor by using "this"
        this(name,salary,null);
    }

    public void display()
    {
        System.out.println("Employee Name :"+name);
        System.out.println("Department : "+dept);
        System.out.println("Employee Salary : "+salary);
    } 

}

// Creating Objects for Class Employee
/**
 *
 * @author Sudarsan
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here

        //Passing parameters to the Employee Constructor
        
        Employee e=new Employee("Hrithik",20000.00,"Direction");
        e.display();

        Employee e1=new Employee("Hrithik",2000.00);
        e1.display();
    }

}

If we compile the above program we can see the fallowing output

Employee Name :Hrithik
Department : Direction
Employee Salary : 20000.0
Employee Name :Hrithik
Department : null
Employee Salary : 2000.0

Here you can observe that department name becomes null in the second constructor call.

Have a look at the fallowing example to know more about constructor overloading

// To fine the Volume of the Cuboid and Cube
/**
 *
 * @author Sudarsan
 */
public class Cuboid {

        double length;
 double width;
 double height;

        // Constructor declared which accepts three arguments
 Cuboid(double l, double w, double h)
 {
  length = l;
  width = w;
  height = h;
 }
 // Overloaded constructor declared which accepts one argument
 Cuboid(double side)
 {
  length = width = height = side;
 }
 double volume()
 {
  return length*width*height;
 }
}

// Constructing Cuboid Objects and passing Parameters
/**
 *
 * @author Sudarsan
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here

        Cuboid cub1 = new Cuboid(1, 2, 5);
 Cuboid cub2 = new Cuboid(3);

        double vol;
        
 vol = cub1.volume();

        System.out.println("Volume of the Cuboid is: "+ vol);

        vol = cub2.volume();

        System.out.println("Volume of the Cube is :" + vol);

    }

}

If we compile this program we can see the below output

Volume of the Cuboid is: 10.0
Volume of the Cube is :27.0