java并发编程学习之一段简单代码证明synchronized锁的是对象

废话不多说，上代码！

public class Thread9 {
public static void main(String[] args) {
Thread9_Util t9 = new Thread9_Util();
Thread9_1 t91 = new Thread9_1(t9);
Thread9_2 t92 = new Thread9_2(t9);
t91.start();
t92.start();
}
}
class Thread9_1 extends Thread{
private Thread9_Util thread9_Util ;
public Thread9_1(Thread9_Util t9){
this.thread9_Util= t9;
}
@Override
public void run() {
thread9_Util.print1(Thread.currentThread().getId());
System.out.println(Thread.currentThread().getId()+"  end");
}
}
class Thread9_2 extends Thread{
private Thread9_Util thread9_Util ;
public Thread9_2(Thread9_Util t9){
this.thread9_Util= t9;
}
@Override
public void run() {
thread9_Util.print2(Thread.currentThread().getId());
System.out.println(Thread.currentThread().getId()+"  end");

}
}
class Thread9_Util {
synchronized void print1(long l){
System.out.println(l);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
synchronized void print2(long l){
System.out.println(l);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}

打印结果：

10

//有延迟

9

10 end

//有延迟

9 end

当然，如果去掉print2中的synchronized方法，打印10和9 的时候是没有延迟时间的，说明，非同步的方法还是能够被其他线程继续访问的。