基本区别：
1、 sleep()来自Thread， wait() 来自Object
2、sleep可以在任何地方使用
wait只能在synchronized方法或者synchronized块中使用 （因为wait会释放锁，所有只有获取了锁，才会释放锁）
最主要的本质区别
Thrad.sleep只会让出CPU，不会导致锁行为的改变
Object.wait不仅让出CPU，还会释放已经占有的同步锁资源
public class WaitSleepDemo {
public static void main(String[] args) {
final Object lock = new Object();
new Thread(new Runnable() {
@Override
public void run() {
System.out.println("thread A is waiting to get lock");
synchronized (lock){
try {
System.out.println("thread A get lock");
Thread.sleep(20);
System.out.println("thread A do wait method");
lock.wait(1000);
System.out.println("thread A is done");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
//为了让Thread A 先于Thread B执行
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
new Thread(new Runnable() {
@Override
public void run() {
System.out.println("thread B is waiting to get lock");
synchronized (lock){
try {
System.out.println("thread B get lock");
System.out.println("thread B is sleeping 10 ms");
Thread.sleep(10);
System.out.println("thread B is done");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
}
}
执行结果：
thread A is waiting to get lock thread A get lock thread B is waiting to get lock thread A do wait method thread B get lock thread B is sleeping 10 ms thread B is done thread A is done
上面的代码验证了： Object.wait不仅让出CPU，还会释放已经占有的同步锁资源
调整后的代码
public class WaitSleepDemo {
public static void main(String[] args) {
final Object lock = new Object();
new Thread(new Runnable() {
@Override
public void run() {
System.out.println("thread A is waiting to get lock");
synchronized (lock){
try {
System.out.println("thread A get lock");
Thread.sleep(20);
System.out.println("thread A do wait method");
//lock.wait(1000);
Thread.sleep(1000);
System.out.println("thread A is done");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
//为了让Thread A 先于Thread B执行
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
new Thread(new Runnable() {
@Override
public void run() {
System.out.println("thread B is waiting to get lock");
synchronized (lock){
try {
System.out.println("thread B get lock");
System.out.println("thread B is sleeping 10 ms");
// Thread.sleep(10);
lock.wait(10);
System.out.println("thread B is done");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();
}
}
打印结果：
thread A is waiting to get lock thread A get lock thread B is waiting to get lock thread A do wait method thread A is done thread B get lock thread B is sleeping 10 ms thread B is done
上面的代码验证了：Thrad.sleep只会让出CPU，不会导致锁行为的改变