Java Project: Tic-Tac-Toe

Example

public class Main {
  static void show(String[][] b) {
    for (String[] row : b) {
      System.out.println(String.join(" | ", row));
    }
  }

  static String winner(String[][] b) {
    for (int i = 0; i < 3; i++) {
      if (!b[i][0].equals(" ") && b[i][0].equals(b[i][1]) && b[i][1].equals(b[i][2])) return b[i][0];
      if (!b[0][i].equals(" ") && b[0][i].equals(b[1][i]) && b[1][i].equals(b[2][i])) return b[0][i];
    }
    return " ";
  }

  public static void main(String[] args) {
    String[][] b = {{" ", " ", " "}, {" ", " ", " "}, {" ", " ", " "}};
    b[0][0] = "X";
    b[1][1] = "O";
    b[0][1] = "X";
    b[0][2] = "X";
    show(b);
    System.out.println("winner: " + winner(b));
  }
}