code: protected String getPropertyPath(Collection<String> parts) {
  
          StringBuilder propertyPath = new StringBuilder();
          Iterator<String> partsIterator = parts.iterator();
          propertyPath.append(partsIterator.next());
          while (partsIterator.hasNext())
              propertyPath.append(".").append(partsIterator.next());
  
          return propertyPath.toString();
      }
docs: Creates a dot-separated string of the given parts.
  @param parts A collections of parts.
  @return a dot-separated string of the parts.