Обсуждение: NullPointerException inside ResultSet.next()

Hi all,

I have a query which returns multiple rows like so:

ResultSet ingredients = st.executeQuery("SELECT * FROM ingredientslookup
WHERE (recipeindex = " + recipes.getInt("recipe_index") + ")");

while (ingredients.next()) {
    // do stuff
}

When I run this query, it iterates through the while loop exactly once,
but then bombs out on the second attempt to evaluate
"ingedients.next()".

java.lang.NullPointerException
        at org.postgresql.jdbc2.ResultSet.next(ResultSet.java:113)

My question is: Should it be possible for this exception to occur inside
this code at all?

Am I making a mistake somewhere, or is this a bug in the jdbc driver?

I have tried both the driver that came with v7.1.3, and the latest v7.2
driver from jdbc.postgresql.org.

Regards,
Graham
--
-----------------------------------------
minfrin@sharp.fm        "There's a moon
                    over Bourbon Street
                        tonight..."

Graham,

It appears you have two result sets open? One for the
recipes.getInt("recipe_index")

Can we see the rest of the code around this?

Dave

-----Original Message-----
From: pgsql-jdbc-owner@postgresql.org
[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Graham Leggett
Sent: Sunday, February 17, 2002 6:45 PM
To: pgsql-jdbc@postgresql.org
Subject: [JDBC] NullPointerException inside ResultSet.next()


Hi all,

I have a query which returns multiple rows like so:

ResultSet ingredients = st.executeQuery("SELECT * FROM ingredientslookup
WHERE (recipeindex = " + recipes.getInt("recipe_index") + ")");

while (ingredients.next()) {
    // do stuff
}

When I run this query, it iterates through the while loop exactly once,
but then bombs out on the second attempt to evaluate
"ingedients.next()".

java.lang.NullPointerException
        at org.postgresql.jdbc2.ResultSet.next(ResultSet.java:113)

My question is: Should it be possible for this exception to occur inside
this code at all?

Am I making a mistake somewhere, or is this a bug in the jdbc driver?

I have tried both the driver that came with v7.1.3, and the latest v7.2
driver from jdbc.postgresql.org.

Regards,
Graham
--
-----------------------------------------
minfrin@sharp.fm        "There's a moon
                    over Bourbon Street
                        tonight..."

Dave Cramer wrote:

> It appears you have two result sets open? One for the
> recipes.getInt("recipe_index")
>
> Can we see the rest of the code around this?

There were two result sets open on the same Statement variable, but with
two different statements. When the first resultset was accessed after
the second statement had been fired off, the driver triggered a
NullPointerException.

Creating separate Statement variables fixed the problem - thanks for
pointing me in the right direction...!

Regards,
Graham
--
-----------------------------------------
minfrin@sharp.fm        "There's a moon
                    over Bourbon Street
                        tonight..."