Yep, resume-driven development. I remember at a previous company a small group of people pushed a Go rewrite to speed everything up. The serious speed improvements came from re-architecting (elimination of a heavy custom framework, using a message queue instead of handling requests synchronously etc). They would have been better off fixing the original system so that everything could benefit from the improvements, not just the tiny bits that they carved off.

Then the next annual report talked about improved scalability because of this amazing technology from Google.

Resume driven development would be using some random ass Java framework to pad on resume. Apple using Apple technologies seems rather like corporate mandate.

If Apple does not dogfood their own technology for production systems what chance do they have to tell 3rd party users that Swift is ready for prime time.

Delving into Java arcana instead of getting first hand experience in developing in Swift would've been great opportunity wasted to improve Swift.

I agree if this was a brand new system.

However, they chose to replace an existing system with swift. The "arcana" I mentioned is start up options easily found and safe to apply. It's about as magical as "-O2" is to C++.

Sure, this may have been the right choice if the reason was to exercise swift. However, that shouldn't pretend like there was nothing to do to make Java better. The steps I described are like 1 or 2 days worth of dev work. How much time do you think a rewrite took?

Apple has explicitly stating that they want to try and move as much of their stuff to Swift as possible.

I’m sure you’re right, there must’ve been ways to improve the job of deployment. But if they wanted to reduce resource usage and doing it in Swift aligned with some other company goal it would make sense they might just go straight to this.

Once Amazon CEO was asked about new competitors trying to create cloud infrastructure fast. His reply was "You cannot compress experience"

Saving few weeks or months by learning 3rd party technology instead of applying and improving first party technology would be amateurish.

> However, that shouldn't pretend like there was nothing to do to make Java better.

This seems like constant refrain that Apple or anyone choosing their own tech over someone else's owe absolute fair shot to stuff they didn't choose. This is simply not the way world works.

Yes, there are endless stories companies spending enormous resources to optimize Java stack even up to working with Core Java team at Oracle to improve on JVM innards. But those companies are just (although heavy) user of core technology rather than developer of competing one. Apple is not one of those users, they are developers.

> Yes, there are endless stories companies spending enormous resources to optimize Java stack

And not what I'm advocating for. Sometimes rewrites are necessary.

What I'm advocating is exercising a few well documented and fairly well known jvm flags that aren't particularly fiddly.

The jvm does have endless knobs, most of which you shouldn't touch and instead should let the heuristics do their work. These flags I'm mentioning are not that.

Swapping g1gc for zgc, for example, would have resolved one of their major complaints about GC impact under load. If the live set isn't near the max heap size then pause times are sub millisecond.

> This seems like constant refrain that Apple or anyone choosing their own tech over someone else's owe absolute fair shot to stuff they didn't choose. This is simply not the way world works.

The reason for this refrain is because Java is a very well known tech, easy to hire for (which Amazon that you cite heavily uses). And Apple had already adopted Java and wrote a product with it (I suspect they have several).

I would not be saying any of this if the article was a generic benchmark and comparison of Java with swift. I would not fault Apple for saying "we are rewriting in swift to minimize the number of languages used internally and improve the swift ecosystem".

I'm taking umbridge to them trying to sell this as an absolute necessity because of performance constraints while making questionable statements on the cause.

And, heck, the need to tweak some flags would be a valid thing to call out in the article "we got the performance we wanted with the default compiler options of Swift. To achieve the same thing with Java requires multiple changes from the default settings". I personally don't find it compelling, but it's honest and would sway someone that wants something that "just works" without fiddling.

I remember the days when Apple developed their own JVM, ported WebObjects from Objective-C to Java, and even had it as the main application language for a little while, uncertain if the Object Pascal/C++ educated developers on their ecosystem would ever bother to learn Objective-C when transitioning to OS X.