DNSJava failing to lookup records?

[Andrew H. <aa...@vo...>]

Folks --

Here at VolunteerMatch we use dnsjava (1.3.3) to do some basic semantic 
verification of user email addresses before they're added to our 
system.  Users enter an email address for most important site actions, 
and we do logical RFC 2822 checks followed by a simple test along the 
lines of 'does this domain have an MX record? if not, does it have an A 
record?'.

On Sunday, after restarting our servlet engine (Jetty 4.2.12 running on 
RH Linux 7.3, Sun JDK 1.4.0), every record lookup was returning null.  
This has happened once before on a brand new machine, and we chalked it 
up to setup problems (we had some problems in our resolv.conf that 
needed fixing).  This time around, though, there weren't any changes in 
the system to cause the problem.  For the record, using dig to lookup 
records from a shell worked fine for the same domains that dnsjava was 
failing on.

My first guess was that dnsjava simply had some problems reading or 
parsing resolv.conf, and thus the initialization step was booched, but 
that doesn't make much sense to me given that on any normal day it 
doesn't have this problem.  I'm about to dive into the code to try and 
figure out what's going on, but can anyone offhand give any ideas?  Has 
anyone seen this problem?

And, most importantly, is there a way to force dnsjava to initialize and 
return some sort if a status code?  I'm not certain what a status code 
would mean in this case, but ideally I'm looking for some way of finding 
what dnsjava is using as name servers, how it decided on them, and 
whether the initialization process had any problems.

Thanks for any help,

- a.

p.s. Yes, the versions of dnsjava and the JDK are old.  They're both 
being upgraded soon, but the question still holds.