Obtain a collection of statistic figures (i.e. sum, average, max, min, count) for all products of given category

Statistics.java

    @RequestMapping("/statistics")
    public DoubleSummaryStatistics getStatistics(@RequestParam("category") final Optional<String> category) {
        return productRepos.findAll().stream().filter(p -> category.get().equalsIgnoreCase(p.getCategory())).
                mapToDouble(p -> p.getPrice()).summaryStatistics();
    }