Re: NullPointer at ResultSet.java:113

Hans,

Oh, ok, now I see what you are trying to do. No you can't close the
statement here, the result set that you are going to scroll through is
part of it.

You can close it safely after you have scrolled through the result set.
It still shouldn't throw an NPE though

Dave

> -----Original Message-----
> From: Hans Deragon [mailto:hans@deragon.biz]
> Sent: Saturday, March 16, 2002 7:26 AM
> To: Dave@micro-automation.net
> Cc: 'pgsql-jdbc'
> Subject: Re: [JDBC] NullPointer at ResultSet.java:113
>
>
> Hi Dave.
>
>
>    I do not see a difference.  If I close a Statement, I
> still get later
> a NullPointerException.
>
>    I have a question, should I actually close a Statement at
> that point
> or not?  I have no clue what I am supposed to do. For the moment, I
> removed the st.close() statement in my code.  Performance and
> resource
> management are not on my list of priorities.
>
>
> Sincerely,
> Hans Deragon
>
> Dave Cramer wrote:
>
> > Hans,
> >
> > I rebuilt the 7.2dev driver on the download site. Let me
> know if that
> > fixes your problem
> >
> > Dave
> >
> >
> >>-----Original Message-----
> >>From: pgsql-jdbc-owner@postgresql.org
> >>[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Hans Deragon
> >>Sent: Thursday, March 14, 2002 6:42 PM
> >>To: Dave@micro-automation.net
> >>Cc: 'pgsql-jdbc'
> >>Subject: Re: [JDBC] NullPointer at ResultSet.java:113
> >>
> >>
> >>Found the problem.  I do:
> >>
> >>   public static void main(String argv[]) throws Exception
> >>   {
> >>     Class.forName("org.postgresql.Driver");
> >>     Connection m_connection =
> >>       DriverManager.getConnection(DATABASEURL, USERNAME, PASSWORD);
> >>
> >>     ResultSet rs =null;
> >>     {
> >>       Statement st = m_connection.createStatement();
> >>       rs = st.executeQuery("SELECT * FROM stocksymbol");
> >>       st.close(); // <------ Problem!
> >>     }
> >>
> >>     System.err.println("\nHANS1" + rs);
> >>     rs.beforeFirst();
> >>     System.err.println("\nHANS1b");
> >>     while(rs.next())
> >>     {
> >>       System.err.println("\nHANS2\n");
> >>     }
> >>
> >>As you can see, the statement is closed before the
> ResultSet is used.
> >>It used to work with old Postgresql drivers, but not the most
> >>recent.  I
> >>  will simply remove the st.close() statement in my close.
> I assume
> >>that there is a finalize() function in the Statement such
> >>that the close
> >>is done automatically when the instance is disposed.
> >>
> >>Still, it would be nice if we got a nice exception instead of a
> >>NullPointer exception.  Can someone correct the code to
> generate such
> >>exception?
> >>
> >>Sorry for the delay for my response. Its a pet project I am
> >>working on,
> >>on spare time.
> >>
> >>
> >>Sincerely,
> >>Hans Deragon
> >>
> >>Dave Cramer wrote:
> >>
> >>
> >>>Hans,
> >>>
> >>>Generally this means that there is nothing in the result
> >>>
> >>set. Can you
> >>
> >>>give me some code which demonstrates this bug?
> >>>
> >>>Dave
> >>>
> >>>-----Original Message-----
> >>>From: pgsql-jdbc-owner@postgresql.org
> >>>[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Hans Deragon
> >>>Sent: Saturday, March 09, 2002 6:13 AM
> >>>To: pgsql-jdbc
> >>>Subject: [JDBC] NullPointer at ResultSet.java:113
> >>>
> >>>
> >>>Greetings.
> >>>
> >>>
> >>>   Upgraded yesterday to the latest pgjdbc2.jar.  I am
> >>>
> >>using JDK 1.4.0.
> >>
> >>>  My database is postgresql-7.1.3-2.  I get:
> >>>
> >>>         at org.postgresql.jdbc2.ResultSet.next(ResultSet.java:113)
> >>>         at
> >>>
> >>marketmanager.database.StockSymbol.list(StockSymbol.java:93)
> >>
> >>>         at
> >>>
> >>>
> >>marketmanager.datacollection.stocks.YahooCollector.fetchDataFr
> >>omWeb(Yaho
> >>
> >>>oCollector.java:56)
> >>>         at
> >>>
> >>>
> >>marketmanager.datacollection.stocks.YahooCollector.fetchData(Y
> >>ahooCollec
> >>
> >>>tor.java:111)
> >>>         at
> >>>marketmanager.datacollection.FetchData.main(FetchData.java:13)
> >>>
> >>>   This is a bug for sure.  If there is something wrong I am doing,
> >>>then
> >>>
> >>>it should have been caught by an exception and report to me
> >>>
> >>what I was
> >>
> >>>doing wrong.  My code works with an older version of the
> >>>
> >>postgresql jdbc
> >>
> >>>driver.  And my code is pretty basic.
> >>>
> >>>   I could not find on the development website the source
> >>>
> >>of this code.
> >>
> >>>  Anybody can provide a pointer?  May I suggest a direct
> >>>
> >>hyperlink to
> >>
> >>>the code to the development site from the
> >>>
> >>http://jdbc.postgresql.org/?
> >>
> >>>
> >>>Ciao
> >>>Hans
> >>>
> >>>
> >>>
> >>>
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> >>>
> >>>
> >>>
> >>
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