Even if a special inv handler exists, we still use the generic one sometimes.

Could you point out the places where wo don't use the special inventory handler.

I've completely forgotten about this issue, but there was a problem with JABBA barrels. Don't exactly recall what it was, or if it was fixed our not. Better ask ProfMobius.

We're using JABBA on 1.7.10 right now. There does not seem to be a problem. I assume it was fixed?

Mobius implemented a workaround. We were causing a lot of lag, and I couldn't pinpoint where exactly we were not using the special handler.

guipsp (or anyone else), feel free to throw a jvisualvm sampled .nps file (maximum sampling rate, atleast 30 seconds worth of recording while the issue is being caused) at me if you ever feel that LP is causing lag, i try to fix things that run slowly.

also, this issue may have been caused by a bug with JABBA whereby reading the contents of a barrel was causing a block update, even though nothing was being changed.

Stacktraces showed that we were using the default inv handler IIRC

Do you mean like this: https://dl.dropboxusercontent.com/u/33855125/LogisticsPipes/profile_1.png ?
Because we create that accessmap BEFORE we wrap the inv if they have a special handler. So in the case in the pic it will still use the special inventory handler for Jabba.

Nah, was calling a codepath that is used for non-special invs in jabba. Again, not sure if it has been fixed or not.