Re: NullPointerException when calling executeQuery() - why?

Rob,

Don't close the connection if you are sending it back to the connection
pool

Dave
On Mon, 2002-04-22 at 09:51, rob wrote:
> I'm experiencing a NullPointerException when calling executeQuery() on a
> PreparedStatement  what are the possible errors I've made?
>
> The code looks a little something like this.
>
> ...
> try {
>
> ps = con.prepareStatement(SELECT_SID);
> ps.setString(1, sid);
> // <-- At this point variables: ps and sid are not null and ps
> // <-- seems to be properly structured as per ps.toString();
> rs = ps.executeQuery(); // <- throws NullPointerException
>
> if (rs.next())
> user = resultsToObject(rs);
>
> } catch (Throwable t) {
>     t.printStackTrace();
>     throw new DatastoreException(t);
> }
> ...
>
> The odd thing is and what may be important is that the exception is not
> thrown the first time the method is called.  It is only thrown every
> time after.  Is this indicitave of me improperly cleaning up from the
> first call?  If so what might I have done?
>
> After each call to the method containing the above code I do the
> following:
>
> rs.close();
> ps.close();
> con.close();
>
> Then I recycle my connection reference to a pool.
>
> Anyway a stack trace follows, if anyone could help I would appreciate
> it thanks.
>
> Rob
>
> java.lang.NullPointerException:
> at org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:61)
> at org.postgresql.Connection.ExecSQL(Connection.java:398)
> at org.postgresql.jdbc2.Statement.execute(Statement.java:130)
> at org.postgresql.jdbc2.Statement.executeQuery(Statement.java:54)
> at
> org.postgresql.jdbc2.PreparedStatement.executeQuery(PreparedStatement.java:99)
> at mapper.UserDAO.findUser(UserDAO.java:76)
> at mapper.UserBO.findUser(UserBO.java:55)
> at domain.User.<init>(User.java:17)
> at web.LoginAction.perform(LoginAction.java:34)
> at
> org.apache.struts.action.ActionServlet.processActionPerform(ActionServlet.java:1787)
> at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1586)
> at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:510)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
>
> .. and the rest of the exception is probably not relevant ...
>
>
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