The javelin, while no longer causing a crash, now can be enchanted with any enchantment possible.

Here is an example of one containing sword, fishing rod, crossbow and armor enchantments.

I just found out though that in the previous update, it could be enchanted with any enchantment then too, just that the incompatible ones like protection wouldn't have an effect, but others like loyalty does work.

Thanks for reporting this, fixed with 1c9f489