Helping , Observable's multithread problem, thread is losting ?

Question

i am practicing an example of Observable and Observer pattern. But one problem were occured as following:
the programe will print out a 10*10 grid , and using observer pattern to change every grid 's color.
The fill rule is that : 1. randomly to choose a beging grid,
2. notify the four grid (left ,right , upper, below of the choosed grid) to change their's grid color.
The problem is when using multithread to notify grid , not all of the grid will be changed color, but if using single thread to notify grid, then all of the grid will be notified, and color changed.
the switch of the multithread and single thread is the P.java 's 62-66 line, and 67-71 line, the source is following, anyone can help to analysing the source, and found exactly where is reason of not all of the grids could be notified , very thanks.
the starup class is the Guess10.java.
the source :
package guess10:
package guess10;
import java.util.*;
import guess10.gui.*;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class P
    implements Observer {
  public P() {
  public P(int x, int y) {
    this.x = x;
    this.y = y;
  public static void main(String[] args) {
    P p1 = new P();
  int x;
  int y;
  public void open() {
//    System.out.println("open " + this);
  public void update() {
//    System.out.println("update " + this);
//    System.out.println("[" + x + "," + y+"]");
    F.instance.getGrid(x, y).action();
  public void open(Observable ob) {
    open();
//    System.out.println(this);
    ob.deleteObserver(this);
  public void update(final Observable ob) {
    update();
    ( (PObservable) ob).change();
//    ob.notifyObservers(new Point[]{new Point(x+1,y)});
//    ob.notifyObservers(new Point[]{new Point(x,y+1)});
//    ob.notifyObservers(new Point[]{new Point(x+1,y+1)});
//    ob.notifyObservers(new Point[]{new Point(x-1,y-1),new Point(x+1,y-1),
//    new Point(x+1,y+1),new Point(x-1,y+1)});
      final Point[] p = new Point[] {
          new Point(x - 1, y), new Point(x, y - 1),
          new Point(x + 1, y), new Point(x, y + 1)
     new Thread(new java.lang.Runnable() {
        public void run() {
            ob.notifyObservers(p);
      },"" + x +"," + y ).start();
//      new java.lang.Runnable() {
//        public void run() {
//          ob.notifyObservers(p);
//      }.run();
  public void update(Observable observable, Object object) {
//    System.out.println(this+" " +Thread.currentThread().getName());
    Point[] p = (Point[]) object;
    for (int i = 0; i < p.length; i++) {
        if (this.x == p.x && this.y == p[i].y) {
if ( ( (PObservable) observable).exist(this)) {
open(observable);
update(observable);
public static int count = 0;
public String toString() {
return "x = " + x + " y = " + y;
// now not used
private Object lock = new Object();
package guess10;
import java.util.*;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class PLayout {
private BitSet xb = new BitSet();
private BitSet yb = new BitSet();
PObservable o = new PObservable();
public PLayout() {
public static void main(String[] args) {
PLayout PLayout1 = new PLayout();
* create 100 p object, and store into Observable object
public void init() {
for (int i = 0; i < 10; i++) {
for (int j = 0; j < 10; j++) {
P p = new P(i, j);
o.addObserver(p);
// todo : need to subclass for the Observable ??
// otherwise , how to set changed to true ?
public void start(int x, int y) {
o.change();
o.notifyObservers(new Point[] {new Point(x, y)});
package guess10;
import java.util.*;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class PObservable
extends Observable {
public PObservable() {
super();
public static void main(String[] args) {
PObservable PObservable1 = new PObservable();
public synchronized void change() {
this.setChanged();
public synchronized boolean exist(P p) {
return v.contains(p);
private Vector v = new Vector();
public synchronized void addObserver(Observer o) {
super.addObserver(o);
v.add(o);
public synchronized void deleteObserver(Observer o) {
super.deleteObserver(o);
v.remove(o);
package guess10;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class Point {
public Point() {
public Point(int x, int y) {
this.x = x;
this.y = y;
public static void main(String[] args) {
Point point1 = new Point();
int x;
int y;
package guess10;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class Guess10 {
public Guess10() {
public static void main(String[] args) {
Guess10 guess101 = new Guess10();
guess101.start();
public void start() {
PLayout pl = new PLayout();
pl.init();
int x = 0;
int y = 0;
java.util.Random random = new java.util.Random(System.currentTimeMillis());
x = random.nextInt(10);
y = random.nextInt(10);
pl.start(x, y);
// try {
// x = System.in.read();
// y = System.in.read();
// catch (IOException ex) {
// ex.printStackTrace();
// if(!isDigit(x) | !isDigit(y)) {
// System.out.println("Not correct number! " + x + " " + y);
// System.exit(1);
// pl.start(x-'0',y-'0');
static boolean isDigit(int ch) {
return ( (ch - '0') | ('9' - ch)) >= 0;
package guess10;
import java.io.*;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class Out {
public Out() {
public static void main(String[] args) {
Out out1 = new Out();
public static final PrintStream out = System.out;
public static void print(PLayout playout) {
the package guess10.gui
package guess10.gui;
import java.awt.*;
import javax.swing.*;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class F
extends JFrame {
public static F instance = new F();
public F() {
super("O G");
init();
setVisible(true);
private Grid[] ps = new Grid[100];
public Grid getGrid(int x, int y) {
return ps[x * 10 + y];
public void init() {
Container con = this.getContentPane();
con.setLayout(new java.awt.GridLayout(10, 10));
for (int i = 0; i < 10; i++) {
for (int j = 0; j < 10; j++) {
con.add(ps[i * 10 + j] = new Grid());
setSize(400, 400);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
public static void main(String[] args) {
F f1 = new F();
f1.getGrid(4, 3).setBackground(Color.yellow);
package guess10.gui;
import java.awt.*;
import javax.swing.*;
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class Grid
extends JPanel {
public Grid() {
super();
this.setBorder(BorderFactory.createEtchedBorder());
// this.add(new javax.swing.JTextField("777"));
public static void main(String[] args) {
Grid grid1 = new Grid();
public void action() {
try {
Thread.currentThread().sleep(100);
catch (InterruptedException ex) {
// this.setBackground(Color.yellow);
this.setBackground(new Color(r--, g--, b++));
// add(new javax.swing.JLabel(Thread.currentThread().getName()+" "+count++));
// this.validate();
private static int r = 255;
private static int g = 230;
private static int b = 128;
private static int count = 0;

Answer 1

copy the java file into notepad, and save to .java file,
then javac guess10\*.java file to compile, and java guess.Guess10 to run , then can see the gui's output,
Only you see the gui's output, you can understand what i describe.
Only seeing the source will not found the reason of the problem, it's need to run indeedly.
is there anyone to try that ?