public Serializable get(String key, String group){
    try{
      PreparedStatement prep = this.conn.prepareStatement("SELECT value FROM keyval WHERE key = ? AND collection = ?");
      prep.setString(1, key);
      prep.setString(2, group);
      ResultSet rs = prep.executeQuery(); 
      if(!rs.next()){
        return null;
      }
      ObjectInputStream objStr = new ObjectInputStream(new ByteArrayInputStream(rs.getBytes(1)));
      rs.close();
      Serializable obj = (Serializable)objStr.readObject();
      return obj;
    }catch(SQLException e){
      e.printStackTrace();
      return null;
    }catch(IOException e){
      e.printStackTrace();
      return null;
    }catch(ClassNotFoundException e){
      e.printStackTrace();
      return null;
    }
  }