This length of metal is weighted to keep the spike at its tip foremost as it sails through the air.
Javelins are a type of ranged weapon. They deal 3-11 damage (clumping 3), meaning 7 points of damage on average and have a strength requirement of 15. While intended to be thrown, you can wield them as a melee weapon. If your strength is sufficient they are better than your starting dagger, and nearly the equal of a sword or axe. They are never cursed, enchanted or runic.
Swords: Dagger · Sword · Broadsword — Axes: Axe · War Axe

Polearms: Spear · War Pike — Maces: Mace · War Hammer
Misc: Rapier · Whip · Flail
Ranged: Darts · Incendiary Darts · Javelins