基本區別：
1、 sleep()來自Thread， wait() 來自Object
2、sleep可以在任何地方使用
wait只能在synchronized方法或者synchronized塊中使用 （因為wait會釋放鎖，所有只有獲取了鎖，才會釋放鎖）
最主要的本質區別
Thrad.sleep只會讓出CPU，不會導致鎖行為的改變
Object.wait不僅讓出CPU，還會釋放已經占有的同步鎖資源
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();
//為了讓Thread A 先於Thread B執行
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();
}
}
執行結果：
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
上面的代碼驗證了： Object.wait不僅讓出CPU，還會釋放已經占有的同步鎖資源
調整后的代碼
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();
//為了讓Thread A 先於Thread B執行
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();
}
}
打印結果：
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
上面的代碼驗證了：Thrad.sleep只會讓出CPU，不會導致鎖行為的改變