> I can talk only from .NET provider perspective, but the reason is,
> that the implementation is native.

Same reason with Jaybird - loading a third-party DLL into JVM decreases
stability. Any serious error in fbclient.dll crashes whole JVM. In case
of pure Java driver the exceptions affect only part that work with
driver. Also multithreading - Jaybird is natively multithreaded,
fbclient.dll, if I am not mistaken, has a global mutex (that was an
issue with InterClient JDBC driver).

Roman