No, it is not part of the unmodded game.
Nope. You HAVE to download a minecraft mod to have it.
Impossible.
you cant
You don't: Minecraft is a game based in Java and will not run without Java. Not to mention that Minecraft isn't free either. Sure, there are other ways of getting Minecraft for free, but I'm not telling you to do that.
You can play it in browser.
you can play minecraft classic in browser in minecraft.net
You can't. You can play other games like it. But not minecraft.
yes, in the demo
By downloading it from minecraft.net
on juegosjuegos-com
You absolutely MUST have Java to play or run Minecraft, and there is no legal online version of Minecraft. You must download Minecraft to your computer.