You need Java Development Kit (JDK). Which you already have if you are playing minecraft. You need the Minecraft Coders Pack (to help look at the code for minecraft) and Eclipse, a program that lets you look at Java code in Class files in your minecraft.JAR. This code is what the game runs off of. From here I recommend going on the Forums and look at a tutorial for begginers. I did this too and I am on my way to releasing my first mod.
Not in the current Vanilla (Minecraft without Mods) Minecraft, no. But their are a few Mods out there that will make that possible.
you can get minecraft mods and textures off the minecraft mods website.
You cannot make a hang glider in Minecraft without mods.
There is no brass in MineCraft without mods.
Yes. Most mods in Minecraft are free, however you can donate to the developer to help them improve and make new mods.
As for now, chocolate is not in Minecraft. But you can install mods to add chocolate.
Yes, most Minecraft Mods are updatable.
there are no mods in minecraft pe i hope there will be
bearshare is not required to get minecraft mods.
Without using mods, you can't.
Yes, Minecraft mods are free. However, they can be harmful to your game and your computer and Mojang cannot do anything about it since they did not make the mod.
you can get most minecraft mods off the minecraft mods website, or you can google.