Java program to explain Interface and static

MainProgram.java

package student;

import java.util.Scanner;

interface AadharCardProcess {
    abstract void GetUsername(String user);

    abstract void GetPhonenumber(int number);

    abstract void CreateAadharnumber(int newAadharnumber);
}

class AadharCard implements AadharCardProcess {
    public String username;
    public int aadharnumber;
    private int phonenumber;

    static int totalUsers = 0;

    @Override
    public void GetUsername(String user) {
        this.username = user;
    }

    @Override
    public void GetPhonenumber(int number) {
        this.phonenumber = number;
    }

    @Override
    public void CreateAadharnumber(int newAadharnumber) {
        this.aadharnumber = newAadharnumber;
    }

    public void showPerson() {
        System.out.println("Username : " + this.username);
        System.out.println("Phone number : " + this.phonenumber);
        System.out.println("Aadhar number : " + this.aadharnumber);
    }

}

public class MainProgram {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        AadharCard a1 = new AadharCard();
        System.out.println("Enter the username : ");
        String username = s.next();
        a1.GetUsername(username);
        System.out.println("Enter the phone number : ");
        a1.GetPhonenumber(s.nextInt());
        System.out.println("Enter the aadhar card number : ");
        a1.CreateAadharnumber(s.nextInt());
        //s.close();
        a1.showPerson();
        AadharCard.totalUsers++;

        Scanner s1 = new Scanner(System.in);
        AadharCard a2 = new AadharCard();
        System.out.println("Enter the username : ");
        String username1 = s1.next();
        a2.GetUsername(username1);
        System.out.println("Enter the phone number : ");
        a2.GetPhonenumber(s1.nextInt());
        System.out.println("Enter the aadhar card number : ");
        a2.CreateAadharnumber(s1.nextInt());
        //s1.close();
        a2.showPerson();
        AadharCard.totalUsers++;

        Scanner s2 = new Scanner(System.in);
        AadharCard a3 = new AadharCard();
        System.out.println("Enter the username : ");
        String username2 = s2.next();
        a3.GetUsername(username2);
        System.out.println("Enter the phone number : ");
        a3.GetPhonenumber(s2.nextInt());
        System.out.println("Enter the aadhar card number : ");
        a3.CreateAadharnumber(s2.nextInt());
        //s2.close();
        a3.showPerson();
        AadharCard.totalUsers++;

        System.out.println("Total Aadhar users added : " + AadharCard.totalUsers);
    }
}