Constructor in Java

A constructor in Java is a special method that is used to initialize objects.

• a constructor method name should be the same as the class name
• a constructor method can be method overloading.
• an object is created using the new() keyword, a constructor is called.
• It calls a default constructor if there is no constructor available in the class

sample/People.java

package sample;

public class People {
    private String name;
    private String country;
    private String language;

    public People(){
        System.out.println("Empty Constructor is called");
    }

    public People(String name, String country, String language){
        System.out.println("A Constructor with three parameters is called");
        this.name = name;
        this.country = country;
        this.language = language;
    }

    public String getName(){
        return this.name;

    }
}

There are two constructors which are people an empty parameter constructor, and a constructor with three parameters. getName method will use to get the object’s name that will be set up by calling a constructor with three parameters.

sample/Main.java

package sample;

public class Main {
    public static void main(String[] args) {

        People tim = new People();
        
        // Using the constructor method, initialize an object.
        People mike = new People("Mike", "Spain", "Spanish");
        System.out.println(mike.getName());
    }
}

Empty Constructor is called
A Constructor with three parameters is called
Mike

• When a tim object is created, an empty constructor is called.
• When a mike object is created, a constructor with three parameters is called.

You can see with the method is called with printed messages. Also, with a constructor, you do not have to set a value individually. You will see a constructor extensively in Java because constructors are a very important part of creating objects from classes.