两个线程交替打印字母 java

package com.example.socket;

public class test {

private static Object LOCK = new Object();
private static boolean flag = false;

class A extends Thread{
public void run() {
for (int c = 0; c <= 10; c++) {
synchronized (LOCK) {

System.out.println("a");

if(!flag){
flag = true;
LOCK.notify(); //在这里虽然唤醒了另一个线程b，但锁并没有释放

try {
LOCK.wait();//在wait后的瞬间线程b得到锁

} catch (InterruptedException e) {
e.printStackTrace();
}

}
}

}
}

}

class B extends Thread{
public void run() {
for (int c = 0; c <= 10; c++) {
synchronized (LOCK) {

System.out.println("b");

if(flag){
flag = false;
LOCK.notify();

try {

LOCK.wait();

} catch (InterruptedException e) {
e.printStackTrace();
}

}
}

}
}

}
public static void main(String[] args) {
test x = new test();

x.new A().start();
x.new B().start();
}
}