第一次写博客，问大家一个问题吧。

本人编辑了一个java五子棋程序，但是运行时出现了问题

import java.util.Scanner;

public class FIve {
    public static void main(String[] args) {
        new FIve().run();
    }
    public void run() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入黑棋昵称");
        String nameBlack = scanner.nextLine();
        System.out.println("请输入白棋昵称");
        String nameWhite = scanner.nextLine();

        int size = 15;
        int[][] table = new int[size][size];

        printTable(table, size);

        int win = 0;
        int currentPlayer = 0;
        do {
            //  下棋
            String playerName = currentPlayer == 0 ? nameBlack : nameWhite;
            System.out.println("该" + playerName + "下棋");

            int x, y;
            boolean canPlace = true;
            do{
                if (!canPlace){
                    System.out.println("这个位置不能放棋子，请重新输入");
                }
                String code = scanner.nextLine();
                y = code.charAt(0) - 'A';
                x = Integer.valueOf(code.substring(1)) - 1;

                canPlace = true;
                canPlace = canPlace && x >= 0 && x < size;
                canPlace = canPlace && y >= 0 && y < size;
                canPlace = canPlace && table[y][x] == 0;
            }while (!canPlace);

            table[y][x] = currentPlayer == 0 ? 1 : 2;
            currentPlayer++;
            currentPlayer %= 2;
            //  打印棋盘
            printTable(table, size);
            //  检测输赢
            win = check(table, x, y );
        } while (win == 0) ;

        if (win == 1) {
            System.out.println(nameBlack + "胜利");
        } else if (win == 2) {
            System.out.println(nameWhite + "胜利");
        } else if (win == 3) {
            System.out.println("平局");
        }
    }


    public void printTable(int[][] table, int size) {
        System.out.print("   ");
        for (int i = 0; i < size; i++) {
            int value = i + 1;
            System.out.print(value < 10 ? value + "  " : value + " ");
        }
        System.out.println();

        for (int i = 0; i < size; i++) {
            char title = (char) ('A' + i);
            System.out.print(title + "   ");
            for (int j = 0; j < size; j++) {
                int value = table[i][j];
                char c = ' ';
                switch (value) {
                    case 0: c = '.'; break;
                    case 1: c = 'x'; break;
                    case 2: c = 'o'; break;
                }
                System.out.print(c + "  ");
            }
            System.out.println();
        }
    }
    public int check(int[][] table, int x, int y){
    boolean test = false;
    test = test || moreThaFive(table, x, y, 0, -1);
    test = test || moreThaFive(table, x, y, 1, -1);
    test = test || moreThaFive(table, x, y, 1, 0);
    test = test || moreThaFive(table, x, y, 1, 1);

    if (test){
        return table[y][x];
    }
    return 0;
    }

    public boolean moreThaFive(int[][] table, int x, int y, int dx, int dy){
        int count = 0;
        count += count(table, x, y, dx, dy);
        count += count(table, x, y, -dx, -dy);
        count -= 1;
        return count >= 5;
    }

    public int count(int[][] table, int originX, int originY, int dx, int dy){
        int originValue = table[originY][originX];
        int count = 0;
        int x = originX;
        int y = originY;

        int value;
        do {
            count ++;
            originX += dx;
            originY += dy;
            value = table[originY][originX];
        } while (value == originValue);
        return count;
    }
}

当黑棋输入第一个棋子时，就会出现错误警告，然后程序就会莫名结束。