No idea, it's been years since I last worked on it. It was also not the only Go service written at Apple (90% of cloud services at Apple were written in Java), though it may have been the first one used in production.
And I sit here kind of shocked that Apple would use Java for anything, backend or not. I thought Apple had a strong preference for owning its own tech stacks, whether that be ObjC/WebObjects or later Swift...
I think WebObjects was supporting Java even before it came to Apple from Next. In the early days, many of Apple's services built with WebObjects even ran on Sun server hardware, and XServe's. But nowadays it's all commodity Linux hardware, like you would find in any data center.
Not sure why you'd be shocked, it's a solid language for enterprise services like Apple offers, and their other languages - C/C++, Objective-C, Swift - aren't very kind for web services.
Great use case for Go though, especially its concurrency features for web crawlers. I reckon Scala could work too, although it's a lot more complicated / clever.
I would guess because the input sanitizing requirement is harder for the web; having a stackoverflow when running locally requires the attacker to execute locally -- having a use-after-free from port 80 would be a much wider audience
Some Apple services were written in C/C++. One downside is it's very hard to source engineers across the company who can then work on that code, or for those engineers to go work on other teams.
Apple employs the founder of the Netty project, who has given plenty of open talks about Apple’s use of Netty (which implies Java services). Same is true for Cassandra.
Apple had a very odd obsession with Java right after the NeXT purchase. WebObjects got converted and they tried to do a Java Cocoa. Both were worse than the original.
