Tell me ... why it's only netflix what makes CPU go on max? Why netflix is giving me info message when I turn on VPN in the middle of movie? Why it's only netflix who stop working another second when my internet connection has quick failure?
Sorry but it seems that you have no idea how netflix really works.
Do you even know what a frontend/client is vs a backend?
The frontend is anything but java (the website uses javascript, they have mobile apps, not sure what they are written in, but besides android having a few necessary wrappers, these are also not java applications).
You don’t see the backend and they do different things between different services so not much point in comparing them - that’s a huge, complex, partially cached-at-your-ISP even network infrastructure.
Besides, Java itself is very fast and is itself no reason for an applications’ (especially network-related) bad performance. It literally runs like half of the internet, with basically every other top 100 IT companies having business-critical infrastructure dependent on it.
The point that the others are trying to make is that these questions are not relevant in the context of the backend technology choices. The REST or GraphQL endpoints could be handled by monkeys writing bits via typewriters and it wouldn't affect the CPU usage in your browser.
Alright, its clear that either you’re a troll or you don’t realise that you have no idea what you’re talking about, either way there’s no point going further into this conversation