Javelins believe it or not, are members of the rodent family.
javelins
No
<http://www.javeland.com/> is a reliable site for high quality javelins of various weights and makes.
Yes
Yes
Initial javelins were made of wood until the mid-1950's. Dick Held improved javelin aerodynamics and durability by introducing aluminum javelins around that time (his brother, Bud, was the world-record holder for a time). Current javelins are made of steel, aluminum and/or carbon fiber.
iron
800g
wood and iron
The plural for for javelin is javelins.
A roof and a building