​```java
public class Test extents Thread {
    public void run() {
      // 重写Thread的run方法
      System.out.println("dream");
    }
    
    public static void main(String[] args) {
        new Test().start();
    }
}
​```

​```java
public class Test {
    public static void main(String[] args) {
        new Thread(() -> {
            System.out.println("dream");
        }).start();
    } 
}
​```

public class Test {
    public static void main(String[] args) {
        // FutureTask 构造方法包装了Callable和Runnable。
        FutureTask<Integer> task = new FutureTask<>(() -> {
            System.out.println("dream");
            return 0;
        });
        new Thread(task).start();
    }
}
​```

​```java
public class Test {
    public static void main(String[] args) {
        ExecutorService threadPool = Executors.newFixedThreadPool(1);
        threadPool.submit(() -> {
            System.out.println("dream");
        });
        threadPool.shutdown();
    }
}

@FunctionalInterface
public interface Runnable {
   /**
    * 被线程执行，没有返回值也无法抛出异常
    */
    public abstract void run();
}

@FunctionalInterface
public interface Callable<V> {
    /**
     * 计算结果，或在无法这样做时抛出异常。
     * @return 计算得出的结果
     * @throws 如果无法计算结果，则抛出异常
     */
    V call() throws Exception;
}