code: @Override
  	public boolean isReadonly() {
  
  		if (isIdProperty() || isVersionProperty()) {
  			return false;
  		}
  
  		Indexed indexedAnnotation = getIndexAnnotation();
  		if (indexedAnnotation != null && indexedAnnotation.readonly()) {
  			return true;
  		}
  		if (indexedAnnotation == null && getFieldAnnotation() == null) {
  			return true;
  		}
  		return false;
  	}
docs: /*
  (non-Javadoc)
  @see org.springframework.data.solr.core.mapping.SolrPersistentProperty#isReadonly()