null pointer exception

[Periya.Data <per...@gm...>]

Right. I did a print of dns_hdr.toString(). All the 4 sections are 0. Hence,
getQuestion, as you pointed out, returns null.

       byte[] dns_msg_buf= new byte[2048];
        bb.get(dns_msg_buf, 71, caplen);
        Message dns_msg = new Message(dns_msg_buf);
        System.out.println("Message size: " + dns_msg.numBytes());
        Header dns_hdr = dns_msg.getHeader();
        System.out.println("DNS Header: " + dns_hdr.toString());

DNS Header: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 0
;; flags: ; qd: 0 an: 0 au: 0 ad: 0

On Thu, Sep 1, 2011 at 3:26 PM, Brian Wellington <bwe...@xb...> wrote:

>
> On Sep 1, 2011, at 3:23 PM, Periya.Data wrote:
>
> Also, I get a null pointer exception error when I try to getName.
>
>       // DNS Questions
>         Name qname;
>         int qtype;
>         int qclass;
>
>         Record question = dns_msg.getQuestion();
>         qname = question.getName();        ===> error at this line.
>
> I am not what that means.  A valid record is not found? Is there a nice way
> to check if a valid record has been returned? Maybe I am screwing up with
> the starting of a valid DNS message from the bytebuffer.
>
>
> As I said before, there's a problem with your data.  If you're parsing a
> message, and the DNS header indicates that there are 0 records in all of the
> sections, the message parser won't try to parse any records, so
> Message.getQuestion() would return null.
>
> Brian
>