Думаю что мое решение подходит, но проблема в валидаторе? Скажите, прав ли я?

public class Solution {
    public static void main(String[] args) {
        Solution solution = new Solution();
        Properties properties = solution.getProperties("4.JavaCollections/src/com/javarush/task/task31/task3109/properties.xml");
        properties.list(System.out);

        properties = solution.getProperties("4.JavaCollections/src/com/javarush/task/task31/task3109/properties.txt");
        properties.list(System.out);

        properties = solution.getProperties("4.JavaCollections/src/com/javarush/task/task31/task3109/notExists");
        properties.list(System.out);
    }

    public Properties getProperties(String fileName) {
        Properties properties = new Properties();
        Path path = Paths.get(fileName);
        String subStr = fileName.substring(fileName.lastIndexOf("/")+1,fileName.length());
        if (fileName.endsWith(".xml")) {
            try {
                properties.loadFromXML(new FileInputStream(fileName));
            } catch (Exception e) {
                return null;
            }
        } else if(subStr.contains(".")){
            try {
                properties.load(new FileReader(fileName));

            } catch (Exception e) {
                return null;
            }
        }
        return properties;
    }
}