I am wondering can Elf druid use his weapon familarity and not voilate his/her druidic code ie using a short or long bow?
Druid can use any weapon he is proficient with. It is forbidden to wear metal armor for him.
Some GMs have separate 'Codes' for the Classes that have such. A friend's 3.5 game has at least 6 Druid 'orders' that differ primarily in Fluff, although each has serious mechanical differences, too. The Elf bunch are not allowed as Evil or Lawful, use bows and have set lists of companions and forms they may take. A 'Human' bunch has strong ties to Elementals, MUST be true neutral, gain the ability to do all manner of awesome Elemental stuff, but get no armor and crappy weapons.The Golden Bough, photocopied from my campaign is about as pure RAW as you'll find except they're mostly LN, and work with civilization to protect the natural world.
As Drejk mentions, they are not prohibited from using certain weapons, only armor:
Weapon and Armor Proficiency: Druids are proficient with the following weapons: club, dagger, dart, quarterstaff, scimitar, scythe, sickle, shortspear, sling, and spear. They are also proficient with all natural attacks (claw, bite, and so forth) of any form they assume with wild shape (see below).Druids are proficient with light and medium armor but are prohibited from wearing metal armor; thus, they may wear only padded, leather, or hide armor. A druid may also wear wooden armor that has been altered by the ironwood spell so that it functions as though it were steel. Druids are proficient with shields (except tower shields) but must use only those crafted from wood.
A druid who wears prohibited armor or uses a prohibited shield is unable to cast druid spells or use any of her supernatural or spell-like class abilities while doing so and for 24 hours thereafter.