public class MyThread extends Thread{ 
    public void run(){ 
        System.out.println("hello world");
    }
}
public static void main(String[] args) { 
    MyThread t = new MyThread();
    t.start();
}

public class MyThread implements Runnable{ 
    public void run(){ 
        System.out.println("hello world");
    }
}
public static void main(String[] args) { 
    MyThread t = new MyThread();
    new Thread(t).start();
}

public class MyThread implements Callable<String>{ 
    public String call(){ 
        return "hello world";
    }
}
public static void main(String[] args) throws Exception{ 
    MyThread t = new MyThread();
    FutureTask<String> task = new FutureTask<>(t);
    new Thread(task).start();
    System.out.println(task.get());
    System.out.println(task.isDone());
    System.out.println(task.isCancelled());
    System.out.println(task.cancel(true));
}

public static void main(String[] args) { 
    ExecutorService executor = Executors.newCachedThreadPool();
    executor.execute(new Runnable() { 
        public void run() { 
            System.out.println("hello world");
        }
    })
    executor.shutdown();
}

public static void main(String[] args) { 
    new Thread(){ 
        public void run() { 
            System.out.println("hello world");
        }
    }
    .start();
}