O que ele chama apos um showMessageDialog?

// Tour do Cavalo \

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.DecimalFormat;

public class D722 extends JApplet implements ActionListener {

  // board[row][col]
  int[][] board = new int[8][8], useAccessibility= new int[8][8];
  int accessibility[][] = {
        {2,3,4,4,4,4,3,2},
        {3,4,6,6,6,6,4,3},
        {4,6,8,8,8,8,6,4},
        {4,6,8,8,8,8,6,4},
        {4,6,8,8,8,8,6,4},
        {4,6,8,8,8,8,6,4},
        {3,4,6,6,6,6,4,3},
        {2,3,4,4,4,4,3,2},
    };

  int[] horizontal = new int[8], vertical = new int [8];
  int currentCol = 0, currentRow = 0;

  JTextArea txtBoard;
  JTextField txtX, txtY;
  JButton btnAction;

  public void init() {

    // Array de movimentos \

    horizontal[0] =  2;
    horizontal[1] =  1;
    horizontal[2] = -1;
    horizontal[3] = -2;
    horizontal[4] = -2;
    horizontal[5] = -1;
    horizontal[6] =  1;
    horizontal[7] =  2;

    vertical[0] = -1;
    vertical[1] = -2;
    vertical[2] = -2;
    vertical[3] = -1;
    vertical[4] =  1;
    vertical[5] =  2;
    vertical[6] =  2;
    vertical[7] =  1;

    Container c = getContentPane();
    c.setLayout (new FlowLayout());

    txtBoard = new JTextArea();
    c.add( txtBoard );

    txtX = new JTextField(5);
    c.add(txtX);

    txtY = new JTextField(5);
    c.add(txtY);

    btnAction = new JButton("Ação!");
    btnAction.addActionListener(this);
    c.add( btnAction );
  }

  public void actionPerformed (ActionEvent e) {

    currentRow = Integer.parseInt( txtX.getText() );
    currentCol = Integer.parseInt( txtY.getText() );

    heuristicMove();
  }

  // Zera a matriz
  public void resetBoard() {
    for (int x = 0; x < board.length; x++)
      for (int y = 0; y < board[x].length; y++){
        board[x][y] = 0;
        useAccessibility[x][y] = accessibility[x][y];
      }
  }

  // Mostra resultado da matriz board[][] no txtBoard
  public void showBoard() {
    String output="";
    DecimalFormat df = new DecimalFormat("00");

    for (int x = 0; x < board.length; x++){
      for (int y = 0; y < board[x].length; y++) {
        if (board[x][y] > 0)
          output += " " + String.valueOf(df.format(board[x][y])) + " ";
        else
          output += " [] ";
      }
      output += "\n";
    }

    txtBoard.setFont( new Font("Lucida Console",Font.PLAIN,20) );
    txtBoard.setText(output) ;
    
    //*****
    JOptionPane.showMessageDialog(null,"Passing by");    
    
  }

  // Testa se vai sair do tabuleiro ou se posição já foi visitada
  public int testMove() {
    int lowAcc = 10, testAcc = -1, useMove = -1;
    int minusAcc[] = new int[8];

    for (int i=0; i <8; i++) minusAcc[i] = 0;

    for (int x=0; x < 8; x++){
      if (testMove(x)) {
        minusAcc[x] = 1;
        testAcc = getAccessiblityByMove(x);
        if (testAcc < lowAcc) {
          lowAcc = testAcc;
          useMove = x;
        }
      }
    }

    for (int z=0; z <8; z++){
      if (minusAcc[z] == 1) {
       reduceAccessibility(currentRow + horizontal[z], currentCol + vertical[z]);
      }
    }

    return useMove;
  }

  public boolean testMove(int n) {
    if ( currentRow + horizontal[n] > 7 || currentRow + horizontal[n] < 0 )
      return false;
    if ( currentCol + vertical[n] > 7 || currentCol + vertical[n] < 0)
      return false;

    int testRow = 0, testCol = 0;

    testRow = currentRow + horizontal[n];
    testCol = currentCol + vertical[n];

    if ( board[testRow][testCol] > 0 )
      return false;
    else
      return true;
  }

  public void reduceAccessibility(int row, int col) {
    useAccessibility[row][col] -= 1;
  }

  public int getAccessiblityByMove(int n) {
    int testRow = 0, testCol = 0;

    testRow = currentRow + horizontal[n];
    testCol = currentCol + vertical[n];

    return useAccessibility[testRow][testCol];
  }

  //Efetua o moviemento pelo codigo
  public void doMove(int n, int c) {
    currentRow += horizontal[n];
    currentCol += vertical[n];

    board[currentRow][currentCol] = c;
  }


  public void heuristicMove() {
    int moveCount = 0, moveN = 0;
    resetBoard();

    for (moveCount = 1; moveCount < 65; moveCount++) {
      moveN = testMove();
      if (moveN >= 0){
        showBoard();
        try {
          Thread.sleep(100);
        }
        catch (InterruptedException ex) {
        }
        doMove(moveN, moveCount);
      } else {
        System.out.println("Breaking " + moveN);
        break;
      }
    }

    showBoard();
    JOptionPane.showMessageDialog(null,"Movimentos:" + (moveCount-1),"",JOptionPane.INFORMATION_MESSAGE);
  }
}