I'm having a hell of a time trying to figure out how to make captured stones disappear. I've read everywhere that I should use the FloodFill algorithm, but I havent had any luck with that so far. Any help would be amazing! Here is my code:

package Go;

import static java.lang.Math.; import static stdlib.StdDraw.; import java.awt.Color;

public class Go2 {

public static Color opposite(Color player) {
    if (player == WHITE) {
        return BLACK;
    }
    return WHITE;
}

public static void drawGame(Color[][] board) {
    Color[][][] unit = new Color[400][19][19];
    for (int h = 0; h < 400; h++) {
        for (int x = 0; x < 19; x++) {
            for (int y = 0; y < 19; y++) {
                unit[h][x][y] = YELLOW;
            }
        }
    }
    setXscale(0, 19);
    setYscale(0, 19);
    clear(YELLOW);
    setPenColor(BLACK);
    line(0, 0, 0, 19);
    line(19, 19, 19, 0);
    line(0, 19, 19, 19);
    line(0, 0, 19, 0);
    for (double i = 0; i < 19; i++) {
        line(0.0, i, 19, i);
        line(i, 0.0, i, 19);
    }
    for (int x = 0; x < 19; x++) {
        for (int y = 0; y < 19; y++) {
            if (board[x][y] != YELLOW) {
                setPenColor(board[x][y]);
                filledCircle(x, y, 0.47);
                setPenColor(GRAY);
                circle(x, y, 0.47);
            }
        }
    }
    int h = 0;

}

public static void main(String[] args) {
    int px;
    int py;
    Color[][] temp = new Color[19][19];
    Color[][] board = new Color[19][19];
    Color player = WHITE;
    for (int i = 0; i < 19; i++) {
        for (int h = 0; h < 19; h++) {
            board[i][h] = YELLOW;
            temp[i][h] = YELLOW;
        }
    }
    while (true) {
        drawGame(board);
        while (!mousePressed()) {

        }
        px = (int) round(mouseX());
        py = (int) round(mouseY());
        board[px][py] = player;
        while (mousePressed()) {

        }
        floodFill(px, py, player, board, temp);
        System.out.print("XXXXX = "+ temp[px][py]);
        if (checkTemp(temp, board, px, py)) {
            for (int x = 0; x < 19; x++) {
                for (int y = 0; y < 19; y++) {
                    if (temp[x][y] == GRAY) {
                        board[x][y] = YELLOW;
                    }
                }
            }
        }
        player = opposite(player);
    }
}

private static boolean checkTemp(Color[][] temp, Color[][] board, int x,
        int y) {
    if (x < 19 && x > -1 && y < 19 && y > -1) {
        if (temp[x + 1][y] == YELLOW || temp[x - 1][y] == YELLOW
                || temp[x][y - 1] == YELLOW || temp[x][y + 1] == YELLOW) {
            return false;
        }
    }
    if (x == 18) {
        if (temp[x - 1][y] == YELLOW || temp[x][y - 1] == YELLOW
                || temp[x][y + 1] == YELLOW) {
            return false;
        }
    }
    if (y == 18) {
        if (temp[x + 1][y] == YELLOW || temp[x - 1][y] == YELLOW
                || temp[x][y - 1] == YELLOW) {
            return false;
        }
    }
    if (y == 0) {
        if (temp[x + 1][y] == YELLOW || temp[x - 1][y] == YELLOW
                || temp[x][y + 1] == YELLOW) {
            return false;
        }
    }
    if (x == 0) {
        if (temp[x + 1][y] == YELLOW || temp[x][y - 1] == YELLOW
                || temp[x][y + 1] == YELLOW) {
            return false;
        }
    }

    else {
        if (x < 19) {
            if (temp[x + 1][y] == GRAY) {
                checkTemp(temp, board, x + 1, y);
            }
        }
        if (x >= 0) {
            if (temp[x - 1][y] == GRAY) {
                checkTemp(temp, board, x - 1, y);
            }
        }
        if (y < 19) {
            if (temp[x][y + 1] == GRAY) {
                checkTemp(temp, board, x, y + 1);
            }
        }
        if (y >= 0) {
            if (temp[x][y - 1] == GRAY) {
                checkTemp(temp, board, x, y - 1);
            }
        }
    }
    return true;
}

private static void floodFill(int x, int y, Color player, Color[][] board,
        Color[][] temp) {
    if (board[x][y] != player) {
        return;
    } else {
        temp[x][y] = GRAY;
        System.out.println("x = " + x + " y = " + y);
        if (x < 19) {
            floodFill(x + 1, y, player, board, temp);
        }
        if (x >= 0) {
            floodFill(x - 1, y, player, board, temp);
        }
        if (y < 19) {
            floodFill(x, y + 1, player, board, temp);
        }
        if (y >= 0) {
            floodFill(x, y - 1, player, board, temp);
        }
    }
}

}