Constructor Overloading in Java

Constructor overloading in Java allows you to define multiple constructors for a class, each with a different set of parameters. This enables you to create objects in various ways, providing flexibility and convenience to the users of your class. Overloaded constructors have the same name but differ in the number or type of parameters they accept.

Syntax for defining overloaded constructors:

public class ClassName {
    // Fields and methods of the class

    // First constructor with no parameters
    public ClassName() {
        // Constructor body
    }

    // Second constructor with one or more parameters
    public ClassName(parameterType1 param1, parameterType2 param2, ...) {
        // Constructor body
    }

    // Additional constructors with different parameter combinations if needed
    // ...
}

Example of constructor overloading:

Let’s create a simple Person class with two overloaded constructors:

public class Person {
    private String name;
    private int age;

    // First constructor with no parameters
    public Person() {
        this.name = "Unknown";
        this.age = 0;
    }

    // Second constructor with parameters to initialize name and age
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    // Additional constructors with different parameter combinations if needed
    // For example, let's add a constructor with only name as a parameter
    public Person(String name) {
        this.name = name;
        this.age = 0; // Default age
    }

    // Methods and other members of the class
    // ...
}

Usage of the Person class:

public class Main {
    public static void main(String[] args) {
        // Using different constructors to create objects
        Person person1 = new Person(); // Uses the constructor with no parameters
        Person person2 = new Person("John", 30); // Uses the constructor with name and age parameters
        Person person3 = new Person("Alice"); // Uses the constructor with only name parameter
    }
}

In this example, the Person class has three constructors: one with no parameters, one with name and age parameters, and one with only the name parameter. Users can create Person objects using the constructor that suits their needs best.