Read transactions don't work on 7.0.x db's

The following code fails on a 7.0 db, but works on a 7.1 db

It works fine with the 7.0 jar, but not with the latest code

I had a quick look and everything looks ok. I am going to keep looking
but I thought I would throw this out and see if anyone knows what is
going on

Dave

package test;
import java.sql.*;
/**
* Title:
* Description:
* Copyright: Copyright (c) 2001
* Company:
* @author
* @version 1.0
*/

public class TransactionSelect {

public TransactionSelect()
{
}
public static Connection getConnection( String url, String user,
String password)
{
try {
Class.forName("org.postgresql.Driver");
return java.sql.DriverManager.getConnection(url,user,password);
} catch(ClassNotFoundException ex) {
ex.printStackTrace(System.out);
} catch(SQLException ex) {
ex.printStackTrace(System.out);
}
return null;
}

public static void main(String[] args)
{

try{
Connection con =
getConnection("jdbc:postgresql://192.168.1.1/davec","davec","");
if (con == null){
throw new RuntimeException("no Connection");
}
con.setAutoCommit(false);
PreparedStatement pstmt = con.prepareStatement("select * from
categories" );
ResultSet rs = pstmt.executeQuery();
con.commit();
con.close();
}catch (SQLException ex){
ex.printStackTrace(System.out);
}
}
}