Derby Mystery..!!!!

Hi
Could anyone please advice me about a strange behavior of derby Database?

1. I have created a table in an Embedded Derby Database with the name "PC"
2. In this table there is a field with the name "EMPID" type of INT, and it is accepting null entries.
3. I have created the dbconnection
dBconnection = DriverManager.getConnection(connString + database,
user, password);
4. I have created a Result Set and a Prepared Statement as well:
private PreparedStatement readXrPc;
private ResultSet resultSet;
5. Then I created the initialize prepare statement:
readXrPc = dBconnection.prepareStatement("SELECT * FROM
APP.PC WHERE EMPID=?");
6. Then I created a method in order to read the records I want..
public ArrayList<PcClass> readEmpIdPc(int ypid){
try{
readXrPc.setInt(1, ypid);
resultSet = readXrPc.executeQuery();......
7. I called the method with ypid=25 (I have at least two entries with this ID in my table)..

Nothing happens.. the result set is empty..
When i run the same SQL qyery in the SQL editor everything is Ok and i have the correct results..

I changed the select statement to "SELECT * FROM APP.PC" and I override the method "toString" in roder to see what entries we have in the result set for the field EMPID..

I saw that when this field has one entry (everything not only the 25 i am looking for) the result is the number 1..
And when there is no entry (null) the result is 0...

Could anyone knows what is going wrong here..?

:(:(:(

just a newbie also...
but in my case...i have to connect using Netbeans..in SERVICES tab.
when connected..it will display as follows:
2011-01-22 21:37:05.044 GMT : Security manager installed using the Basic server security policy.
2011-01-22 21:37:10.046 GMT : Apache Derby Network Server - 10.5.3.0 - (802917) started and ready to accept connections on port 1527

Well, in your create table statement, did you designate the column as "NOT NULL"?

Can you show us the code where to loop through the resultset?