problem with serialization

Hi! I am new here.

I did a small test to try object serialization with the
org.postgresql.util.Serialize class.

I get the following exception when I try to use the at
org.postgresql.util.Serialize.create Method. :

java.lang.NullPointerException
at org.postgresql.jdbc2.ResultSet.getString(ResultSet.java:148)
at org.postgresql.util.Serialize.create(Serialize.java:241)
at org.postgresql.util.Serialize.create(Serialize.java:220)

I looked at create in Serialization.java and saw that
the exception occurs at getString although I have no table corresponding
to the class I want to serialize.
if(!rs.next()){
// String lolo=rs.getString(1);}
}

Although the resultset is empty (because the table is absent) , why
getString has been run ?

Can you help me ?

Chris