It's true, Java bytecode was basically designed for small size. The goal was to transmit java apps quickly over the internet, a hope which mostly died off as JS took over, but which in some ways has been reborn with android (dalvik bytecode is somewhat different but is definitely small). The main tradeoff for the small size is a total lack of optimization until the JIT compilation stage.
But there's no way it's anything like a 10x difference. There's definitely something else going on here, like some quirk about how the app store is calculating the sizes of assets.
I'm talking about the binaries themselves as they are output from dex2oat. The 10x difference is I suspect a product of needing to compile parts of the standard library in addition to the app's code.
But there's no way it's anything like a 10x difference. There's definitely something else going on here, like some quirk about how the app store is calculating the sizes of assets.