code: @Nullable
      public static String[] nullableArrayOfStrings(@Nullable List<Object> list) {
          if (list == null || list.isEmpty()) {
              return null;
          } else {
              final String[] strings = new String[list.size()];
  
              //noinspection ForLoopReplaceableByForEach -> on Android it's faster
              for (int i = 0; i < list.size(); i++) {
                  final Object arg = list.get(i);
                  strings[i] = arg != null ? arg.toString() : "null";
              }
              return strings;
          }
      }
docs: Converts list of objects to nullable array of strings.
  
  @param list list of objects that will be converted to array of strings.
  @return nullable array of strings.