Employing Future and Callable for result-bearing task execution

In Java, Future and Callable are used together to execute tasks asynchronously and obtain results at a later point in time:

• Callable interface: A functional interface that represents a task capable of producing a result:
  • call(): This method encapsulates the task’s logic and returns the result
• Future interface: This represents the eventual completion (or failure) of a Callable task and its associated result:
  • get(): This method retrieves the result, blocking if necessary until completion
  • isDone(): This method checks whether the task is finished
  • Submitting tasks: ExecutorService accepts Callables, returning Futures for tracking completion and results

Here is an example of Callable and Future interfaces:

ExecutorService executor = Executors.newFixedThreadPool(2);
Callable<Integer> task = () -> {
    // perform some computation
    return 42;
};
Future...