A constructor is a special method for initializing a new instance of a class.

The constructor method for a class will have the same name as the class.

The example below shows a class and a constructor named Circle:

 public class Circle {

    public int x = 0;
    public int y = 0;
    public int radius = 0;

    public Circle(int x, int y, int radius) {
        this.x = x;
        this.y = y;
        this.radius = radius;

A class may have multiple constructors. In this case, each constructor will have the same name, but will have different arguments.

A no-argument constructor is a constructor which does not take any arguments.