编写一个简单程序，分别用两种线程的创建方式来生成线程。

在Java中，有两种主要的方式来创建线程：继承Thread类和实现Runnable接口。以下是两个示例：

**1. 继承Thread类**

public class MyThread extends Thread {
    private String name;

    public MyThread(String name) {
        this.name = name;
    }

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println(name + ": " + i);
        }
    }

    public static void main(String[] args) {
        MyThread thread1 = new MyThread("Thread 1");
        MyThread thread2 = new MyThread("Thread 2");

        // 启动线程
        thread1.start();
        thread2.start();
    }
}

**2. 实现Runnable接口**

public class MyRunnable implements Runnable {
    private String name;

    public MyRunnable(String name) {
        this.name = name;
    }

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println(name + ": " + i);
        }
    }

    public static void main(String[] args) {
        Thread thread1 = new Thread(new MyRunnable("Thread 1"));
        Thread thread2 = new Thread(new MyRunnable("Thread 2"));

        // 启动线程
        thread1.start();
        thread2.start();
    }
}

在这两个例子中，我们创建了两个线程，每个线程都有自己的名字，并打印出从0到4的数字。`start()`方法用于启动线程执行。