在Java中實現Active對象模式，可以通過創建一個包含線程池的類來實現

1. 首先，創建一個實現Runnable接口的ActiveObject類：

public class ActiveObject implements Runnable {
    private final BlockingQueue<Runnable> queue;

    public ActiveObject() {
        this.queue = new LinkedBlockingQueue<>();
    }

    @Override
    public void run() {
        while (true) {
            try {
                Runnable task = queue.take();
                task.run();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                break;
            }
        }
    }

    public void addTask(Runnable task) {
        try {
            queue.put(task);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }
}

2. 創建一個包含線程池的ActiveObjectManager類：

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

public class ActiveObjectManager {
    private final ExecutorService executorService;

    public ActiveObjectManager(int numberOfThreads) {
        this.executorService = Executors.newFixedThreadPool(numberOfThreads);
    }

    public void submit(ActiveObject activeObject) {
        executorService.submit(activeObject);
    }

    public void shutdown() {
        executorService.shutdown();
    }
}

3. 使用ActiveObject和ActiveObjectManager：

public class Main {
    public static void main(String[] args) {
        int numberOfThreads = 4;
        ActiveObjectManager manager = new ActiveObjectManager(numberOfThreads);

        ActiveObject activeObject1 = new ActiveObject();
        ActiveObject activeObject2 = new ActiveObject();

        manager.submit(activeObject1);
        manager.submit(activeObject2);

        activeObject1.addTask(() -> System.out.println("Task 1 executed by ActiveObject 1"));
        activeObject1.addTask(() -> System.out.println("Task 2 executed by ActiveObject 1"));

        activeObject2.addTask(() -> System.out.println("Task 1 executed by ActiveObject 2"));
        activeObject2.addTask(() -> System.out.println("Task 2 executed by ActiveObject 2"));

        manager.shutdown();
    }
}

這個示例中，我們創建了兩個ActiveObject實例，并將它們提交給ActiveObjectManager。然后，我們向這些ActiveObject實例添加任務，這些任務將由線程池中的線程執行。最后，我們關閉線程池。