What is the relationship between the Future and Callable interfaces in programming languages?

In Java, the Callable interface represents a task that returns a result and can throw exceptions. It is similar to Runnable but with the ability to return a value.

The Future interface represents the result of an asynchronous operation, allowing you to check if the task is complete, get the result, or cancel the execution.

The relationship between them:

• Callable is used to describe a task that needs to be executed.
• Future is returned when submitting a Callable for execution (for example, via ExecutorService), and allows you to obtain the result of the Callable in the future.

Example:

ExecutorService executor = Executors.newSingleThreadExecutor();
Callable<Integer> task = () -> {
    Thread.sleep(1000);
    return 123;
};
Future<Integer> future = executor.submit(task);
// ...
Integer result = future.get(); // blocks until the task is complete
executor.shutdown();