volatile 與 synchronized 使用

volatile 範例:

public class ExampleRunnable implements Runnable{
    private volatile int j;
    @Override
    public void run() {
        
        for (j = 0; j < 10; j+=2){
            System.out.println("j = " + j);
        }
    }   
}

Demo 一下，看看執行結果：

public class ThreadDemo {
    public static void main(String[] args){ 

        ExampleRunnable er1 = new ExampleRunnable();

        Thread t1 = new Thread(er1);
        Thread t2 = new Thread(er1);
        Thread t3 = new Thread(er1);
        t1.start();
        t2.start();
        t3.start();
        
    }
}

syhchronized 範例：