限制一次运行的最大线程数的正确方法是什么？

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

public class ThreadPoolExample {
    public static void main(String[] args) {
        // 创建一个固定大小的线程池
        ExecutorService executor = Executors.newFixedThreadPool(10);

        for (int i = 0; i < 20; i++) {
            Runnable worker = new WorkerThread("" + i);
            executor.execute(worker);
        }

        // 关闭线程池
        executor.shutdown();
        while (!executor.isTerminated()) {
        }
        System.out.println("Finished all threads");
    }
}

class WorkerThread implements Runnable {
    private String command;

    public WorkerThread(String s) {
        this.command = s;
    }

    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + " Start. Command = " + command);
        processCommand();
        System.out.println(Thread.currentThread().getName() + " End.");
    }

    private void processCommand() {
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    public String toString() {
        return this.command;
    }
}

import java.util.concurrent.Semaphore;

public class SemaphoreExample {
    private static final int MAX_THREADS = 10;
    private static Semaphore semaphore = new Semaphore(MAX_THREADS);

    public static void main(String[] args) {
        for (int i = 0; i < 20; i++) {
            new Thread(new WorkerThread("" + i)).start();
        }
    }

    static class WorkerThread implements Runnable {
        private String command;

        public WorkerThread(String s) {
            this.command = s;
        }

        @Override
        public void run() {
            try {
                semaphore.acquire();
                System.out.println(Thread.currentThread().getName() + " Start. Command = " + command);
                processCommand();
                System.out.println(Thread.currentThread().getName() + " End.");
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                semaphore.release();
            }
        }

        private void processCommand() {
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        @Override
        public String toString() {
            return this.command;
        }
    }
}