Sudoku Verifier

import java.util.Scanner;
import java.lang.*;
import java.util.*;

/**
 * Write a program to perform verification for a Sudoku board.
 *
 * @author your name here
 * @version 0.1
 */
public class DefectiveSudoku
{
    /**
     * Determine if a Sudoku board is in a legal configuration.
     * The board may be partially complete, in which case empty
     * cells are represented by a dot (.).
     * @param board a string containing the symbols in a 9x9 or
     * 16x16 Sudoku board in row-major order.
     * @pre board.length() is 81 or 256
     * @pre board 9x9 board uses symbols 1-9, 16x16 board uses A-P (uppercase).
     * @return true if the board configuration is legal, false otherwise.
     * That is, no row,
     * column or square contains a duplicate symbol.
     */
    public boolean verify(String board)
    {
        if (board.length() == 81 || board.length() == 256)
        {
            int save = board.length();
            int stop = 0;
            int k = 0;

            save = (int) Math.sqrt(save);

            for (int i = save; i < save * save + save; i = i + save)
            {
                if (!verifyNumberOnce(board.substring(i - save, i), save))
                {
                    return false;
                }
            }

            for (int i = 0; i < save; i++)
            {
                String boardCol = "";
                for (int j = i; j < save * save; j = j + save)
                {
                    boardCol = boardCol + board.charAt(j);
                }

                if (!verifyNumberOnce(boardCol, save))
                {
                    return false;
                }
            }

            if (save == 9)
            {
                if (!verifyNine(board))
                {
                    return false;
                }
            }
            else if (save == 16)
            {
                if (!verifySixteen(board))
                {
                    return false;
                }
            }
        }
        else
        {
        return false;
        }

        return true;
    }

    /**
     * When Sudoku board is 9x9.
     *
     * @pre     The data holding the data for the boxes part of the Sudoku.
     */
    public boolean verifyNine(String board)
    {
        for (int i = 0; i < 63; i = i + 3)
        {
            if (i == 9) i = 27;
            if (i == 36) i = 54;
            String boardThrees = "";

            boardThrees = boardThrees + board.charAt(i)
                + board.charAt(i + 1) + board.charAt(i + 2);
            boardThrees = boardThrees + board.charAt(i + 9)
                + board.charAt(i + 1 + 9) + board.charAt(i + 2 + 9);
            boardThrees = boardThrees + board.charAt(i + 18)
                + board.charAt(i + 1 + 18) + board.charAt(i + 2 + 18);

            if (verifyNumberOnce(boardThrees, 9))
            {
                return true;
            }

        }
        return true;
    }

    /**
     * When Sudoku board is 16x16.
     *
     * @pre     The data holding the data for the boxes part of the Sudoku.
     */
    public boolean verifySixteen(String board)
    {
        for (int i = 0; i < 208; i = i + 4)
        {
            if (i == 16)
            {
                i = 64;
            }
            if (i == 80)
            {
                i = 128;
            }
            if (i == 144)
            {
                i = 192;
            }
            String boardFours = "";

            boardFours = boardFours + board.charAt(i)
            + board.charAt(i + 1) + board.charAt(i + 2) + board.charAt(i + 3);
            boardFours = boardFours + board.charAt(i + 16)
                + board.charAt(i + 1 + 16) + board.charAt(i + 2 + 16)
                + board.charAt(i + 3 + 16);
            boardFours = boardFours + board.charAt(i + 32)
                + board.charAt(i + 1 + 32) + board.charAt(i + 2 + 32)
                + board.charAt(i + 3 + 32);
            boardFours = boardFours + board.charAt(i + 48)
                + board.charAt(i + 1 + 48) + board.charAt(i + 2 + 48)
                + board.charAt(i + 3 + 48);

            if (!verifyNumberOnce(boardFours, 16))
            {
                return false;
            }

        }
        return true;
    }

    /**
     * When Sudoku board is split up. Check to see if split up part is valid.
     *
     * @pre     The data holding the data for the split part of the Sudoku.
     */
    public boolean verifyNumberOnce(String board, int save)
    {
        for (int i = 0; i < board.length(); i++)
        {
            for (int j = 0; j < board.length(); j++)
            {
                if (board.charAt(i) == board.charAt(j)
                    && board.charAt(j) != '.'
                    && i != j)
                {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * A local main for console testing.
     * Get the data to calculate if Sudoku is valid.
     *
     * @pre     The data holding the data of the Sudoku.
     */
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNextLine())
        {
            String str = sc.nextLine();
            DefectiveSudoku app = new DefectiveSudoku();
            System.out.println(app.verify(str));
        }
    }

}