import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class App {
    private static final int COUNT = 10;
    public static void main( String[] args ) throws InterruptedException {
        // 10回カウントするCountDownLatchを生成
        CountDownLatch countDownLatch = new CountDownLatch(COUNT);
        // Threadを3つ生成するExecutorServiceを生成
        ExecutorService exec = Executors.newFixedThreadPool(3);
        for (int i = 0; i < COUNT; i++) {
            exec.submit(new TestRunnable(countDownLatch));
        }
        // 各TestRunnableオブジェクトに渡したcountDownLatchオブジェクト
        // のカウントダウンがすべて修了するまで待ち受け。
        countDownLatch.await();
        System.out.println("finished!");
    }
}