Decimal to Hexadecimal

/* Write a program that enters a positive integer number
 * and converts and prints it in hexadecimal form. */

import java.util.Scanner;

public class _05_DecimalToHexadecimal {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter a positive Integer number: ");
        int decimalNum = scan.nextInt();

        // Short variants:
        // String hexadecimalStr =
        // Integer.toHexString(decimalNum).toUpperCase();
        //
        // or:
        // String hexadecimalStr = String.format("%X", decimalNum);

        // Custom variant, also works with negative Integers:
        String hexadecimalStr = "";
        do {
            int rights4BitsValue = decimalNum & 15;
            String hexadecimalSymb = convert4BitsValueToHexadecimalSymbol(rights4BitsValue);
            hexadecimalStr = hexadecimalSymb + hexadecimalStr;
            decimalNum >>>= 4;
        } while (decimalNum != 0);

        System.out.printf("That number in Hexadecimal system is: %s !%n",
                hexadecimalStr);
    }

    private static String convert4BitsValueToHexadecimalSymbol(int bitsValue) {
        switch (bitsValue) {
        case 10:
            return "A";
        case 11:
            return "B";
        case 12:
            return "C";
        case 13:
            return "D";
        case 14:
            return "E";
        case 15:
            return "F";
        default:
            return "" + bitsValue;
        }
    }

}