validating the Aadhar card number in a application

I think you are looking for Verhoeff algorithm, because UIDAI uses this algorithm for validating the aadhar number. You just need to create and use below class.

class VerhoeffAlgorithm{
        static int[][] d  = new int[][]
                {
                        {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
                        {1, 2, 3, 4, 0, 6, 7, 8, 9, 5},
                        {2, 3, 4, 0, 1, 7, 8, 9, 5, 6},
                        {3, 4, 0, 1, 2, 8, 9, 5, 6, 7},
                        {4, 0, 1, 2, 3, 9, 5, 6, 7, 8},
                        {5, 9, 8, 7, 6, 0, 4, 3, 2, 1},
                        {6, 5, 9, 8, 7, 1, 0, 4, 3, 2},
                        {7, 6, 5, 9, 8, 2, 1, 0, 4, 3},
                        {8, 7, 6, 5, 9, 3, 2, 1, 0, 4},
                        {9, 8, 7, 6, 5, 4, 3, 2, 1, 0}
                };
        static int[][] p = new int[][]
                {
                        {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
                        {1, 5, 7, 6, 2, 8, 3, 0, 9, 4},
                        {5, 8, 0, 3, 7, 9, 6, 1, 4, 2},
                        {8, 9, 1, 6, 0, 4, 3, 5, 2, 7},
                        {9, 4, 5, 3, 1, 2, 6, 8, 7, 0},
                        {4, 2, 8, 6, 5, 7, 3, 9, 0, 1},
                        {2, 7, 9, 3, 8, 0, 6, 4, 1, 5},
                        {7, 0, 4, 6, 9, 1, 3, 2, 5, 8}
                };
        static int[] inv = {0, 4, 3, 2, 1, 5, 6, 7, 8, 9};

        public static boolean validateVerhoeff(String num){
            int c = 0;
            int[] myArray = StringToReversedIntArray(num);
            for (int i = 0; i < myArray.length; i++){
                c = d[c][p[(i % 8)][myArray[i]]];
            }

            return (c == 0);
        }
        private static int[] StringToReversedIntArray(String num){
            int[] myArray = new int[num.length()];
            for(int i = 0; i < num.length(); i++){
                myArray[i] = Integer.parseInt(num.substring(i, i + 1));
            }
            myArray = Reverse(myArray);
            return myArray;
        }
        private static int[] Reverse(int[] myArray){
            int[] reversed = new int[myArray.length];
            for(int i = 0; i < myArray.length ; i++){
                reversed[i] = myArray[myArray.length - (i + 1)];
            }
            return reversed;
        }
    }

For More Info:-

1. Verhoeff_Algorithm
2. Google groups, Aadhar auth
3. Actual aadhaaar is 11 digits long and not 12

---

EDIT:--

public static boolean validateAadharNumber(String aadharNumber){
        Pattern aadharPattern = Pattern.compile("\\d{12}");
        boolean isValidAadhar = aadharPattern.matcher(aadharNumber).matches();
        if(isValidAadhar){
            isValidAadhar = VerhoeffAlgorithm.validateVerhoeff(aadharNumber);
        }
        return isValidAadhar;
    }

python3

def aadharNumVerify(adharNum: str) -> bool:
    """
    Takes a N digit aadhar number and
    returns a boolean value whether that is Correct or Not
    """
    verhoeff_table_d = (
        (0, 1, 2, 3, 4, 5, 6, 7, 8, 9),
        (1, 2, 3, 4, 0, 6, 7, 8, 9, 5),
        (2, 3, 4, 0, 1, 7, 8, 9, 5, 6),
        (3, 4, 0, 1, 2, 8, 9, 5, 6, 7),
        (4, 0, 1, 2, 3, 9, 5, 6, 7, 8),
        (5, 9, 8, 7, 6, 0, 4, 3, 2, 1),
        (6, 5, 9, 8, 7, 1, 0, 4, 3, 2),
        (7, 6, 5, 9, 8, 2, 1, 0, 4, 3),
        (8, 7, 6, 5, 9, 3, 2, 1, 0, 4),
        (9, 8, 7, 6, 5, 4, 3, 2, 1, 0))

    verhoeff_table_p = (
        (0, 1, 2, 3, 4, 5, 6, 7, 8, 9),
        (1, 5, 7, 6, 2, 8, 3, 0, 9, 4),
        (5, 8, 0, 3, 7, 9, 6, 1, 4, 2),
        (8, 9, 1, 6, 0, 4, 3, 5, 2, 7),
        (9, 4, 5, 3, 1, 2, 6, 8, 7, 0),
        (4, 2, 8, 6, 5, 7, 3, 9, 0, 1),
        (2, 7, 9, 3, 8, 0, 6, 4, 1, 5),
        (7, 0, 4, 6, 9, 1, 3, 2, 5, 8))

    # verhoeff_table_inv = (0, 4, 3, 2, 1, 5, 6, 7, 8, 9)

    def checksum(s: str) -> int:
        """For a given number generates a Verhoeff digit and
        returns number + digit"""
        c = 0
        for i, item in enumerate(reversed(s)):
            c = verhoeff_table_d[c][verhoeff_table_p[i % 8][int(item)]]
        return c

    # Validate Verhoeff checksum
    return checksum(adharNum) == 0 and len(adharNum) == 12