I initially wrote out my original reply to make it clear that it was classification and then the subset that the rule was applicable to.
But, I made the assumption that "(bows and arrows)" made it clear that the rule applied to bows and arrows.
My apologies. No javelin can ever be classified as a bow and arrows, so you can grapple a javelin-wielder.
I find the wording of the rule in my original post ambiguous as to whether it's intended to apply to javelins or not.
I think the "bows and arrows" part makes it clear that it applies to any weapon that is class 4 and bows/arrows. No javelin can ever be classified as a bow and arrows.
If the rule is meant to only apply to bow and arrow, why does it refer to type 4?
Because Bows and Arrows are Class 4 weapons.
If the rule is meant to apply to all type 4 weapons, why is bow and arrow specifically mentioned?
It doesn't. It applies to Class 4 weapons that are bow/arrow subset.