用synchronized(syncObject)看起来比较好如下：
public class test_sync extends Thread {
Integer x = 0;
public test_sync() {
}
public void run() {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
set_x(10);
}
public void set_x(int a) {
x = a;
synchronized (x) {
x.notify();
}
System.out.println("set_x " + x);
}
public int get_x() {
synchronized (x) {
try {
x.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return x;
}
public static void main(String[] args) {
test_sync t = new test_sync();
t.start();
System.out.println("get_x " + t.get_x());
}
}
但是这段代码不能工作！
修改如下:
public class test_sync extends Thread {
Integer x = 0;
public test_sync() {
}
public void run() {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
set_x(10);
}
public void set_x(int a) {
x = a;
synchronized (this) {
notify();
}
System.out.println("set_x " + x);
}
public int get_x() {
synchronized (this) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return x;
}
public static void main(String[] args) {
test_sync t = new test_sync();
t.start();
System.out.println("get_x " + t.get_x());
}
}
把synchronized (x) 改为synchronized (this);
把x.notyfy() 改为notyfy();
把x.wait() 改为wait();
就能工作，里面的差异是什么:
java synchronized(syncObject) 和 synchronized(this)
原文：http://www.cnblogs.com/lion382/p/4044861.html