Localize month name

Localizer.java

   public static String getGermanMonthName( final String monthName ) {
      return getLocalizedMonthName(monthName, Locale.GERMAN);
   }

   public static String getLocalizedMonthName( final String monthName, final Locale locale ) {
      if ( monthName == null || monthName.isBlank() ) {
         return null;
      }
      try {
         final Month month = Month.valueOf(monthName.toUpperCase());
         final MonthDay monthDay = MonthDay.of(month, 1);
         final DateTimeFormatter german = DateTimeFormatter.ofPattern("MMMM", locale);
         return monthDay.format(german);
      }
      catch ( IllegalArgumentException e ) {
         System.err.println(monthName + " is not a valid month");
      }
      return null;
   }