TicTacToe java code correction

import java.awt.Dimension; import java.awt.Font; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class GuiBoard extends JFrame { private static final long serialVersionUID = 3599408058087421691L; private JButton[][] guiBoardButtons = new JButton[3][3]; // Create the Buttons for the TicTacToe Board private JButton createButton() { JButton theButton = new JButton(); theButton.setPreferredSize(new Dimension(50, 50)); Font buttonFont = new Font("Dialog", Font.PLAIN, 72); theButton.setFont(buttonFont); return theButton; } /* * Create the board * Leave on the upper left corner of the screen */ public GuiBoard() { this.setSize(300,300); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setTitle("COSC 1436 TicTacToe"); this.setAlwaysOnTop(true); JPanel panel1 = new JPanel(); panel1.setSize(300,300); panel1.setLayout(new GridLayout(3,3)); for (int row = 0; row < 3; ++row) { for (int col = 0; col < 3; ++col) { JButton newButton = createButton(); newButton.setText(""); guiBoardButtons[row][col] = newButton; panel1.add(newButton); } } this.add(panel1); this.setVisible(true); } /* * Sets the Tic Tac Toe Square with the given value * At Row-Column */ public boolean setSquare(int row,int col, char value) { boolean result = false; if (guiBoardButtons[row][col].getText().isEmpty()) { guiBoardButtons[row][col].setText(Character.toString(value)); result = true; } return result; } }