Follow these steps to implement the example:

1. Create a class named Task that implements the Callable interface parameterized by the String class:

        public class Task implements Callable<String> {

2. Declare a private String attribute called name that will store the name of the task:

        private final String name;

3. Implement the constructor of the class that initializes the name attribute:

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

4. Implement the call() method. Write a message to the console with the actual date and return some text, for example, Hello, world:

        public String call() throws Exception { 
          System.out.printf("%s: Starting at : %s
",name,new Date()); 
          return "Hello, world"; 
        }

5. Implement the main class of the example by creating a class named Main and adding the main() method to it:

        public class Main { 
          public static void main(String[] args) {

6. Create an executor of the ScheduledThreadPoolExecutor class using the newScheduledThreadPool() method of the Executors class, passing 1 as a parameter:

        ScheduledExecutorService executor=Executors
                                           .newScheduledThreadPool(1);

7. Initialize and start a few tasks (five in our case) with the schedule() method of the ScheduledThreadPoolExecutor instance:

        System.out.printf("Main: Starting at: %s
",new Date()); 
        for (int i=0; i<5; i++) { 
          Task task=new Task("Task "+i); 
          executor.schedule(task,i+1 , TimeUnit.SECONDS); 
        }

8. Request the finalization of the executor using the shutdown() method:

        executor.shutdown();

9. Wait for the finalization of all the tasks using the awaitTermination() method of the executor:

        try { 
          executor.awaitTermination(1, TimeUnit.DAYS); 
        } catch (InterruptedException e) { 
          e.printStackTrace(); 
        }

10. Write a message to indicate the time when the program will finish:

        System.out.printf("Main: Ends at: %s
",new Date());