code: public void putPropertyMetadata(PropertyMetadata propertyMetadata) {
      String mappedName = propertyMetadata.getMappedName();
      PropertyMetadata old = propertyMetadataMap.put(mappedName, propertyMetadata);
      if (old != null) {
        String format = "Class %s has two fields, %s and %s, both mapped to the same property "
            + "name, %s";
        String message = String.format(format, clazz.getName(), old.getName(),
            propertyMetadata.getName(), mappedName);
        throw new EntityManagerException(message);
      }
    }
docs: Puts/adds the given property metadata.
  
  @param propertyMetadata
  the property metadata