public class ABTest {
public static void main(String[] args) {
Thread t1 = new Thread(new PrintA());
Thread t2 = new Thread(new PrintB());
t1.start();
t2.start();
}
private static boolean flag = false;
private static Object lock = new Object();
private static class PrintA implements Runnable{
@Override
public void run() {
while (true) {
synchronized (lock) {
while (flag) {
try {
lock.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
System.out.println("A");
flag = true;
lock.notify();
}
}
}
}
private static class PrintB implements Runnable{
@Override
public void run() {
while (true) {
synchronized (lock) {
while (!flag) {
try {
lock.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
System.out.println("B");
flag = false;
lock.notify();
}
}
}
}
}
