T1  ......2....W          N.....5......W               N.....9.......
T2 W           N....4.....W            N......25.......W


synchronized: -> function 

synchronized object


T1, T2
synchronized(object) {
	//code 1
}

T3, T4
synchronized(object) {
	//code 2
}

T5
synchronized(object) {
	//code 3
}
T6
synchronized(object) {
	//code 4
}
T7
synchronized(object) {
	//code 5
}

T1: ....5....W  R.....6.....N->W           R->R......2....N->W
T2:          S..W           R->R.....36....N->W           R->R......4.....

T1:      S......5......N->W
T2:S..N->W             R->R......25......


======================================
T1:     S....5....N->W(?)               R....
T2:..N..W(?)         R.....25.....S..N->W

#Main.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package java2.lesson05;

/**
 *
 * @author diepvan
 */
public class Main {
    public static void main(String[] args) {
        SharedData sharedData = new SharedData();
        
        Thread1 t1 = new Thread1(sharedData);
        Thread2 t2 = new Thread2(sharedData);
        
        t1.start();
        t2.start();
    }
}

#SharedData.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package java2.lesson05;

/**
 *
 * @author diepvan
 */
public class SharedData {
    int rad;

    public int getRad() {
        return rad;
    }

    public void setRad(int rad) {
        this.rad = rad;
    }
}

#Thread1.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package java2.lesson05;

import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author diepvan
 */
public class Thread1 extends Thread{
    SharedData sharedData;

    public Thread1(SharedData sharedData) {
        this.sharedData = sharedData;
    }
    
    @Override
    public void run() {
        try {
            Thread.sleep(100);
        } catch (InterruptedException ex) {
            Logger.getLogger(Thread1.class.getName()).log(Level.SEVERE, null, ex);
        }
        
        Random random = new Random();
        
        for (int i = 0; i < 20; i++) {
            synchronized (sharedData) {
                int rad = random.nextInt(20);
                sharedData.setRad(rad);
                System.out.println("T1: " + rad);
                
                sharedData.notifyAll();
                try {
                    sharedData.wait();
                } catch (InterruptedException ex) {
                    Logger.getLogger(Thread1.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
        
        synchronized (sharedData) {
            sharedData.notifyAll();
        }
        System.out.println("T1 stop");
    }
    
}

#Thread2.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package java2.lesson05;

import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author diepvan
 */
public class Thread2 extends Thread {

    SharedData sharedData;

    public Thread2(SharedData sharedData) {
        this.sharedData = sharedData;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            synchronized (sharedData) {
                sharedData.notifyAll();
                try {
                    sharedData.wait();
                } catch (InterruptedException ex) {
                    Logger.getLogger(Thread1.class.getName()).log(Level.SEVERE, null, ex);
                }

                int rad = sharedData.getRad();
                System.out.println("T2: " + rad * rad);
            }
        }
        
        synchronized (sharedData) {
            sharedData.notifyAll();
        }
        System.out.println("T2 stop");
    }

}