Bob M schreef op 10-2-2014 10:19:
Hi
I am calling derby within a larger java program....................
Step1: I allocate a database "Connection" object
Step2: I allocate a "Statement" object in the connection
Step 3: I execute a SQL SELECT query, the query result is returned in a
"ResultSet" object
so far so good (I update the latest database record, I add a new record and
I delete the oldest record
I then call a data mining program [Weka]
I setup a few Weka models etc......
I then wish to look at the last 100 records in my database, one at a time
The code I have currently is as follows:-
***********************
try {
Statement s = null;
ResultSet rs = null;
rs = s.executeQuery ("SELECT".................);
int k = 0
while (k < 101) {
rs.next();
...
...
}
k++;
}
}
catch (Exception e)
{
myConsole.getOut().println(e);
}
I get the following error:-
java.lang.NullPointerException
do I need to do something further to read my 100 records?
Bob M
Probably this is not where your program is crashing nevertheless you
have this:
Statement s = null;
ResultSet rs = null;
rs = s.executeQuery ("SELECT".................);
since s = null it will throw a npe.
Regards,
Harm-Jan Zwinderman
http://Cebuned.svipr.nl/Cebuned.html
