Java程序  |  51行  |  1.39 KB

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.concurrent.*;

interface I {
}

class A implements I {
    static int x = (int)(10*Math.random());  // Suppress initialization.
}

public class Main {
  public static void main(String[] args) throws Exception {

      final CountDownLatch first = new CountDownLatch(1);
      final CountDownLatch second = new CountDownLatch(1);

      new Thread(new Runnable() {
          public void run() {
              try {
                  synchronized(I.class) {
                      first.countDown();
                      second.await();
                  }
              } catch (Exception e) {
                  e.printStackTrace();
              }
          }
      }).start();

      first.await();
      new A();
      second.countDown();
      System.out.println("Hello, world!");
  }
}