dnsjava - How are DNS query retries controlled using Simple Resolver in DNSJava?

How are DNS query retries controlled using Simple Resolver in DNSJava? Using the same resolver, we see retries of 2 and in some cases 3. It is not clear as to how it is retried. Any help in this regard?

Update - The attempts are consistent on different machines with the same piece of code.

    SimpleResolver           resolver = (dns == null) ? new SimpleResolver() : new     SimpleResolver(dns) ;    resolver.setTimeout(Duration.ofMillis(dnsTimeoutMs));    lookup.setResolver(resolver) ;    lookup.setCache(null);    org.xbill.DNS.Record[]   records = lookup.run() ;