ProcessElegant.java

 public List<Integer> processExpensiveFunctionElegant(List<Integer> inputs, int firstK) {
        try {
            return concurrentWorkExecutor.splitJoin(firstK,
                    inputs,
                    mathService::process,
                    Collectors.toList());

        } catch (Exception ex) {
            log.error("Error processing expensive function", ex);
            return null;
        }
    }