用Java的等待/通知机制实现“厨师一食者”问题。假设分别有6位厨师和6位食者。厨师做一盘菜的时间为3s，食者吃一盘菜的时间为4s。编程实现这一功能

在Java中，我们可以使用`java.util.concurrent`包下的`Semaphore`、`CountDownLatch`或者`CyclicBarrier`来模拟厨师和食者之间的同步问题。这里我们选择`CountDownLatch`和`CyclicBarrier`来解决“厨师一食者”问题，因为它们能够有效地控制任务完成的顺序。

首先，我们需要创建一个`CountDownLatch`用于信号告知所有厨师完成了烹饪，同时还有一个`CyclicBarrier`用于让食者们在收到信号后一起开始用餐：

import java.util.concurrent.*;

public class CookerEaterProblem {
    private static final int NUM_COOKS = 6;
    private static final int NUM_EATERS = 6;
    private static final int COOKING_TIME = 3000; // 3 seconds per dish
    private static final int EATING_TIME = 4000; // 4 seconds per dish

    public static void main(String[] args) throws InterruptedException {
        CountDownLatch cooksDone = new CountDownLatch(NUM_COOKS);
        CyclicBarrier barrier = new CyclicBarrier(NUM_EATERS + 1);

        // Cookers (threads)
        for (int i = 0; i < NUM_COOKS; i++) {
            new Thread(() -> cook(cooksDone, barrier)).start();
        }

        // Eaters (threads)
        for (int i = 0; i < NUM_EATERS; i++) {
            new Thread(() -> eat(barrier)).start();
        }

        // Wait for all cooks to finish
        cooksDone.await();

        System.out.println("All dishes have been cooked and eaten.");
    }

    private static Runnable cook(CountDownLatch cooksDone, CyclicBarrier barrier) {
        return () -> {
            try {
                Thread.sleep(COOKING_TIME); // Simulate cooking time
                System.out.println(Thread.currentThread().getName() + " finished cooking.");
                cooksDone.countDown(); // Signal that a dish is ready
                barrier.await(); // Wait for all eaters or at least one chef to start eating
            } catch (InterruptedException | BrokenBarrierException e) {
                e.printStackTrace();
            }
        };
    }

    private static Runnable eat(CyclicBarrier barrier) {
        return () -> {
            try {
                barrier.await(); // Wait until a dish is ready
                System.out.println(Thread.currentThread().getName() + " started eating.");
                Thread.sleep(EATING_TIME); // Simulate eating time
                System.out.println(Thread.currentThread().getName() + " finished eating.");
            } catch (InterruptedException | BrokenBarrierException e) {
                e.printStackTrace();
            }
        };
    }
}

在这个例子中，厨师们会依次烹饪并释放信号，当所有厨师都完成烹饪后，第一个食者会被唤醒并开始吃饭。其他食者会在屏障处等待，直到有足够的一盘菜可供他们食用。