synchronized修饰方法，保证数据同步准确性，限制线程互斥访问

1.未加synchronized关键，造成访问顺序混乱

package thread;

/**
 * @author xiaolong.zhu.baby@qq.com created on 2015/2/6.
 */
public class Test extends Thread {
public void jump() {
for (int i = 0; i < 100; i++) {
if(i%10==0)
                System.out.println();
            System.out.print(" "+this.currentThread().getName() + ":" + i + "\t"+" ");
        }
    }
@Override
    public void run() {
jump();
    }
public static void main(String[] args) {
Test test = new Test();
        Thread a = new Thread(test, "A");
        Thread b = new Thread(test, "B");
        a.start();
        b.start();
    }
}

运行结果：



2. 添加synchronized进行互斥访问可以解决数据不同步的问题

package thread;

/**
 * @author xiaolong.zhu.baby@qq.com created on 2015/2/6.
 */
public class Test extends Thread {
public synchronized void jump() {
for (int i = 0; i < 100; i++) {
if(i%10==0)
                System.out.println();
            System.out.print(" "+this.currentThread().getName() + ":" + i + "\t"+" ");
        }
    }
@Override
    public void run() {
jump();
    }
public static void main(String[] args) {
Test test = new Test();
        Thread a = new Thread(test, "A");
        Thread b = new Thread(test, "B");
        a.start();
        b.start();
    }
}

运行结果：



总结：使用了synchronized可以使一个线程运行完synchronized所修饰的方法，其他需要排队等候，可以保证数据的准确性。