dnsjava is an implementation of DNS in Java. It supports all defined record types (including the DNSSEC types), and unknown types. It can be used for queries, zone transfers, and dynamic updates. It includes a cache which can be used by clients, and a minimal implementation of a server. It supports TSIG authenticated messages, partial DNSSEC verification, and EDNS0.

dnsjava provides functionality above and beyond that of the InetAddress class. Since it is written in pure Java, dnsjava is fully threadable, and in many cases is faster than using InetAddress.

dnsjava provides both high and low level access to DNS. The high level functions perform queries for records of a given name, type, and class, and return the answer or reason for failure. There are also functions similar to those in the InetAddress class. A cache is used to reduce the number of DNS queries sent. The low level functions allow direct manipulation of DNS messages and records, as well as allowing additional resolver properties to be set.

A simple tool for doing DNS lookups, a 'dig' clone and a dynamic update client are included, as well as a simple authoritative-only server.