code: public Object convertJavaFieldToSqlArgValue(Object fieldVal) throws SQLException {
  		/*
  		 * Limitation here. Some people may want to override the null with their own value in the converter but we
  		 * currently don't allow that. Specifying a default value I guess is a better mechanism.
  		 */
  		if (fieldVal == null) {
  			return null;
  		} else {
  			return fieldConverter.javaToSqlArg(this, fieldVal);
  		}
  	}
docs: Convert a field value to something suitable to be stored in the database.