Facebook android sdk's 'AccessToken.getCur

Question

I'm trying to get user's id like this:

AccessToken.getCurrentAccessToken.getUserId()

and it is returning an id like this:

1493******22153

but when I'm retrieving the id for same user using findmyfbid.com, I'm getting an id like this:

1000******00783

Though both ids when used like this https://facebook.com/id is opening the same profile successfully in browsers.

Why is this happening and what is the difference between these 2 ids?