If you are smart and you can at least fake it that you are a "good guy"[1], then you stand a very good chance, assuming you are able to find out where these MegaCorps advertise. I work for one of them, and I found the ad on craigslist, which I think is unusual.

[1] - or girl, but "good girl" doesn't mean the same thing! If you are female, then I would guess you have to be able to fake that you are "cool", whatever that means.

[edit: When I say 'smart', I don't mean 'really smart', I just mean that you do in fact know javascript and python pretty well as you say]

[edit2: If you are applying for a job programming java, then you should probably at least learn to how to write a class, instantiate an object, match a regex, etc. before going in there. But that will be easy if necessary.]