问测试2D对象数组中的空值

EN

java.lang.ArrayIndexOutOfBoundsException: -1157793070
    at GameBoardPanel.<init>(GameBoardPanel.java:46)
    at TreasureGame.<init>(TreasureGame.java:22)
    at TreasureGame.main(TreasureGame.java:33)

if (gameBoardButtons[row][col] == null)

public class GameBoardPanel extends JPanel
{
    private BoardButton[][] gameBoardButtons;       // BoardButton 2D array that will be used to populate the board
    private final int NUM_TREASURE_BUTTONS = 20;    // Number of treasure buttons that will be added to the array
    private final int NUM_ROWS = 10;                // Number of rows in the array
    private final int NUM_COLS = 10;                // Number of columns in the array

    public GameBoardPanel()
    {
        int treasureButtonInstances = 0;            // Used to count the number of TreasureButton instances

        // Create the 'gameBoardButtons' array and make it a 10x10 array
        gameBoardButtons = new BoardButton[NUM_ROWS][NUM_COLS];

        // Build an object from the Random class that chooses a number between 0-9
        Random randomNumber = new Random(10);

        // Build a while loop that randomly adds 20 different TreasureButton instances to the 'gameBoardButtons' BoardButton array
        while (treasureButtonInstances < NUM_TREASURE_BUTTONS)
        {
            // Obtain two random numbers that will be used to assign a TreasureButton instance to the 'gameBoardButtons' BoardButton array
            int row = randomNumber.nextInt();
            int col = randomNumber.nextInt();

            // If statement that adds an instance of the TreasureButton class if that particular row/column of the 'gameBoardButtons' BoardButton array is empty
            if (gameBoardButtons[row][col] == null)
            {
                // Create an instance of the TreasureButton class and assign it to the particular row/col of our 'gameBoardButtons' BoardButton array
                gameBoardButtons[row][col] = new TreasureButton();

                // Increment the 'treasureButtonInstances' variable, as an instance of the TreasureButton class has been created
                treasureButtonInstances++;
            }// End of the if statement
        }// End of the while loop

        // Build a nested for loop that will populate the rest of the 'gameBoardButtons' BoardButton array
        for (int row = 0; row < NUM_ROWS; row++)
        {
            for (int col = 0; row < NUM_COLS; row++)
            {
                // If statement that will assign an instance of the BoardButton class if that particular row/col of our 'gameBoardButtons" BoardButton array is empty
                if (gameBoardButtons[row][col] == null)
                {
                    // Create an instance of the BoardButton class and assign it to the particular row/col of our 'gameBoardButtons' BoardButton array
                    gameBoardButtons[row][col] = new BoardButton();
                }// End of the if statement
            }//End of the nested for loop
        }// End of the for loop
    }// End of the GameBoardPanel no-arg constructor