code: private Map<String, String> getAttributeOverrides(Class type) {
          Map<String, String> overrides = new LinkedHashMap<String, String>();
          addAttributeOverrides(overrides, "", type);
          return overrides;
      }
docs: generates a collection of javax.persistence.AttributeOverride annotations needed to override nullable=false
  columns since this is not allowed in *Hst-Entities
  
  @param type embeddable class with non-nullable fields
  @return collection of javax.persistence.AttributeOverride annotations needed to set columns to nullable=true