write a JAVA program that asks the user to enter 4-bit binary number and convert it to decimal

import java.util.Scanner;

public class Main
{
  public static void main (String[]args)
  {
      Scanner input = new Scanner (System.in);
      String binaryNumber = "";
      
      System.out.println ("enter first bit:");
      binaryNumber =binaryNumber + input.next();
      System.out.println ("enter second bit:");
      binaryNumber =binaryNumber + input.next();
      System.out.println ("enter third bit:");
      binaryNumber =binaryNumber + input.next();
      System.out.println ("enter forth bit:");
      binaryNumber =binaryNumber + input.next();

  // convert to decimal
  int decimal = Integer.parseInt (binaryNumber, 2); //parseInt() converts any number to a decimal number
  System.out.println (binaryNumber + " in binary = " + decimal + " in decimal.");
}
}