Tic Tac Toe game resetting too quickly

I have a tic tac toe game that has the user(x) playing the cpu(o). The game starts with the cpu placing(o) in the center and will make a move to a random location after the user. The game is set to loop but it resets as soon as there's a winner and doesn't show the "you win/lose banner". Also sometimes the cpu will place it's letter in my location for some reason, still trying to figure it out.

 public class example2

 {
   static boolean checkWinner(String string, JButton buttons []){
    if (buttons[0].getText() .equals("X") && buttons[1].getText()       .equals("X") && buttons[2].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[0].getText() .equals("O") && buttons[1].getText() .equals("O") && buttons[2].getText() .equals("O"))
        //label.setText("You lose");
        return true;

    if (buttons[3].getText() .equals("X") && buttons[4].getText() .equals("X") && buttons[5].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[3].getText() .equals("O") && buttons[4].getText() .equals("O") && buttons[5].getText() .equals("O"))
        //label.setText("You lose");
        return true;            

    if (buttons[6].getText() .equals("X") && buttons[7].getText() .equals("X") && buttons[8].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[6].getText() .equals("O") && buttons[7].getText() .equals("O") && buttons[8].getText() .equals("O"))
        //label.setText("You lose");
        return true;

    if (buttons[0].getText() .equals("X") && buttons[3].getText() .equals("X") && buttons[6].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[0].getText() .equals("O") && buttons[3].getText() .equals("O") && buttons[6].getText() .equals("O"))
        //label.setText("You lose");
        return true;        

    if (buttons[1].getText() .equals("X") && buttons[4].getText() .equals("X") && buttons[7].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[1].getText() .equals("O") && buttons[4].getText() .equals("O") && buttons[7].getText() .equals("O"))
        //label.setText("You lose");
        return true;

    if (buttons[2].getText() .equals("X") && buttons[5].getText() .equals("X") && buttons[8].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[2].getText() .equals("O") && buttons[5].getText() .equals("O") && buttons[8].getText() .equals("O"))
        //label.setText("You lose");
        return true;

    if (buttons[0].getText() .equals("X") && buttons[4].getText() .equals("X") && buttons[8].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[0].getText() .equals("O") && buttons[4].getText() .equals("O") && buttons[8].getText() .equals("O"))
        //label.setText("You lose");
        return true;

    if (buttons[2].getText() .equals("X") && buttons[4].getText() .equals("X") && buttons[6].getText() .equals("X"))
        //label.setText("You win");
        return true;        
    else if (buttons[2].getText() .equals("O") && buttons[4].getText() .equals("O") && buttons[6].getText() .equals("O"))
        //label.setText("You lose");
        return true;        

    return false;
}

main method:

public static void main(String args[])
{   //creating an array of buttons, and adding ActionListeners to them using a for loop.
    JLabel label = new JLabel("Welcome to the tic tac toe game");
    JButton[] buttons = new JButton[9];
    Random rn = new Random();


    for( int i=0; i<9; i++)
    {
         final int temp = i;
         buttons[i] = new JButton("--");
         buttons[i].addActionListener(new ActionListener()
             {


                public void actionPerformed(ActionEvent e)
                {
                    if (buttons[temp].getText() .equals("--"))
                            {
                        String userx = "X";
                        buttons[temp].setText(userx);
                        if(checkWinner("X", buttons))
                        {
                            label.setText("You Win");
                        }
                        buttons[rn.nextInt(9)].setText("O");
                        if (checkWinner("O", buttons)){
                            label.setText("You Lose");
                        }

                        if (label.getText() .equals("You Lose") || label.getText().equals("You Win"))
                        {
                            for(int a =0; a<9; a++)
                            { buttons[a].setText("--");

                            }
                        label.setText("Welcome to the tic tac toe game");
                        }           
                };{
                    }}}         
             );};

    buttons[4].setText("O");

    Box left = createVerticalBox(); 
    for( int j=0; j<3; j++)
    {
        left.add(buttons[j]);

    }
    Box middle = createVerticalBox();
    middle.add(buttons[3]);

    Box center = createHorizontalBox();
    center.add(createGlue());
    center.add(buttons[4]);
    center.add(createGlue());
    middle.add(center);
    middle.add(buttons[5]);

    Box right = createVerticalBox();
    for(int k=6; k<9; k++)
    {
        right.add(buttons[k]);
    }

    Box panel = createHorizontalBox();
    panel.add(left);
    panel.add(middle);
    panel.add(right);

    Box top = createVerticalBox();
    top.add(label);
    top.add(panel);

    JFrame frame = new JFrame();
    frame.add(top);
    frame.pack();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}
}