docs: public List<String> listAttributeValues() {
          List<String> list = new ArrayList<String>();
          Collection<String> names = listAttributeNames();
          for (String name : names) {
              try {
                  Object val = this.getProperty(name);
                  if (val != null) {
                      list.add(name + " : " + val.toString());
                  }
              } catch (Exception e) {
                  throwException("Could not list attribute values. Reason: ", e);
              }
          }
          return list;
      }