private HazelcastSerializationException throwUnknownFieldException(String fieldName) {
   return new HazelcastSerializationException(
       "Unknown field name: '"
           + fieldName
           + "' for ClassDefinition {id: "
           + cd.getClassId()
           + ", version: "
           + cd.getVersion()
           + "}");
 }
 public int getVersion() {
   return cd.getVersion();
 }