L2J Server

I wasn't really sure where this would go, so Off-Topic!

I was wondering how, if possible, one would go about granting users a HP/MP regeneration bonus when sitting, with say a < 40 level requirement.

Under the current condition of L2J, you'd have to modify the core to support this. Alternatively, you can have a jython script running on a timer and looping through all players ingame, then check if they are sitting and what level they are, and reward some extra HP/MP.
However, such a loop will be EXTREMELY heavy on your server, especially in jython where few to no loop optimizations occur. If you have a server of near 100 players, or a small server but on a weak machine, you definitely should NOT use the timer + loop method.
It should not be too hard to do in the core, though...assuming you know Java.

Ah. I don't know a lick of Java, but I may look into it.
My server is only a test server that a few friends and myself play on.

Thanks