To avoid having to cast in client code,

• ARecord.getAddress() should return Inet4Address
• AAAARecord.getAddress() should return Inet6Address (not feasible since Java creates Inet4Address instances for ::ffff:0.0.0.0/96)

I tried to change the return type (adding casts inside the method), but then I got

Failed to execute goal com.github.siom79.japicmp:japicmp-maven-plugin:0.14.0:cmp (check-compatibility) on project dnsjava: Versions of archives indicate a minor change but binary incompatible changes found.

While this changes the public API, usages of those methods should work like before, as the new return types can still be assigned to InetAddress. What could fail with this change is overriding those methods. Maybe the methods or the classes should be final.