Casting an (deserialized) Object as a (custom) subclass.

Question

Haigh,
I'm having trouble casting objects as their subclass.
I'll explain, i have a class that fetches a stored serialized object from a Database.
i can store the objects no problem.
ex. oodb.store(new Machine());
// machine being my custom class that stores information on the running machine (OS,JVM,ip and MAC address etc.)
then when i want to retrive the object
it should work with the method getObjectByID(int idOfObject) which returns an Object
ex. oodb.getObjecyByID(7)
then i create a new instance of machine
Machine computer = (Machine) oodb.getObjectByID(7);
but i get an error saying i cant cast Object (java.lang.Object) as a Machine (ie.iconicaelixia.objects.Machine to be exact)
It worked before!
well a variation of it worked, then i changed the testing class to suit another test.
i've tried the if(Object intanceOf Machine) method aswell, but it never returned true. Eventhough the binary read of the stored object clearly states it is.
Also, on the topic of serialized objects in a database, would it be more effective if my store/fetch methods stored/fetched Class(es) instead of Object(s)?
If so, how would i return a Class?
For Reference here is my Store/Fetch Methods:
public void storeObject(String ClassType,Object ObjectToStore,String indexableInfo)
          try
               indexableInfo = indexableInfo + "$ObjCreated="+new Date().toString();
               if(ClassType==null)
                    ClassType = ObjectToStore.getClass().getName();
               int oID = getAvailableID();
               PreparedStatement ps = nasc.nasc().prepareStatement("Insert into iserv.objects Set OID = ?,Class = ?, Object = ?,Indexable = ? ");
               ps.setInt(1,oID);
               ps.setString(2,ClassType);
               ps.setObject(3,ObjectToStore);
               ps.setString(4,indexableInfo);
               ps.execute();
               ps = null;
          catch (SQLException sqle)
               sqle.printStackTrace();
     public Object getObjectByID(int ObjectID)
          Object rO = null;
          try
               PreparedStatement ps = nasc.nasc().prepareStatement("SELECT OID, OBJECT from iServ.Objects WHERE OID = "+ObjectID);
               ResultSet rs = ps.executeQuery();
               rs.next();
               rO = rs.getObject("OBJECT");
               LastRetrvID = rs.getInt("OID");
               rs.close();
               ps = null;
          catch (SQLException sqle)
               sqle.printStackTrace();
          return rO;
     }Gurbh Míle síle as aon cabhair!

Answer 1

Okay, I'll ask the obvious question:
Why are you trying to store serialized objects? Why not use the usual approach to a relational database, break down the information into attributes and store them in appropriate fields?