I think my team has gotten pretty good at this. We address the "flood of applicants" by tossing out any resumes that don't have some sort of CS or programming on them (about 25%), and favoring, in order, people who have held a programming job, people who have done programming internships, and people who have taken CS classes. A decent GitHub profile will bump you up in the two later categories.
Next is a five minute phone screen. We're a Java shop, so I ask them something dumb, like "what's the difference between public, private, and protected?" Something any Java dev would know; I'm just trying to find out if they have ever actually used the language.[1]
People that pass the phone screen get a Skype interview, where they write code in an IDE. The first half hour or so is chat and trivial problems like "sort this array" or "return true of this String starts with a letter between A-Z, inclusive." They're allowed to Google and use the standard libraries.
Finally, we have a "close to real world" problem for them to work on. It's a standalone, mostly-toy CRUD application, and we'll ask them to add a feature that represents the kind of work they'd be doing. Again, they have their IDE of choice, Stack Overflow, etc.
I don't think we've had a bad hire since we started using this process. Have we turned aside some all-stars that interview poorly? Maybe, but the team we've built is really good at what they do, so I'm pretty happy with the results.
[1] We have hired Senior devs that don't know Java. One of our team leads was a C# guy for a decade or so, but he was smart and available, so we scooped him up. Java is easy to learn. Programming well isn't.
About your last comment - c# was explicitly made similar to java (at least at first, it diverged in time but the basics are close to being a superset of java).
My first job using c# was in 2010, and I have been programming in java since 2002 at that point. I was productive pretty much since the first day & not because I'm a genius - c# is that similar to java...
I suspect that if you'd have hired a php or a python expert they would have taken more time to get used to java (not that that would have meant you shouldn't hire them!)
Oh absolutely. I used to joke that you could convert C# to Java by replacing "string" with "String" and changing the extension.
But really, most of the C-family of languages are similar enough that you can kind of hack your way through pretty quickly, and become mostly-productive in a few weeks.
The family of Go, Java, C#, Python, Kotlin, Javascript, etc etc are all similar enough in theory that "working code" is as close as Googling the right syntax.
After you've been coding for a few years, I think your degree is largely irrelevant. A guy with 20 years of programming knowledge has far, far more than a degree.
Similarly, a candidate could have graduated top of their class from the most prestigious university in the world, but if they've never been able to hold a job for more than six months, that tells me something.
Your last point is interesting and hits close to home for me, from the other end. My current gig is python, but when I got hired I new exactly zero python. But I had been writing software a long time and in the same area (networking & automation) so they scooped me up. Let's just say it's worked out very well, for everyone involved.
filtering for cs is short sighted imo. You're going to see less and less folks holding a cs degree as more folks wisen up to the trap of student debt in the us.
Instead put folks on trials and keep the good performers.
Next is a five minute phone screen. We're a Java shop, so I ask them something dumb, like "what's the difference between public, private, and protected?" Something any Java dev would know; I'm just trying to find out if they have ever actually used the language.[1]
People that pass the phone screen get a Skype interview, where they write code in an IDE. The first half hour or so is chat and trivial problems like "sort this array" or "return true of this String starts with a letter between A-Z, inclusive." They're allowed to Google and use the standard libraries.
Finally, we have a "close to real world" problem for them to work on. It's a standalone, mostly-toy CRUD application, and we'll ask them to add a feature that represents the kind of work they'd be doing. Again, they have their IDE of choice, Stack Overflow, etc.
I don't think we've had a bad hire since we started using this process. Have we turned aside some all-stars that interview poorly? Maybe, but the team we've built is really good at what they do, so I'm pretty happy with the results.
[1] We have hired Senior devs that don't know Java. One of our team leads was a C# guy for a decade or so, but he was smart and available, so we scooped him up. Java is easy to learn. Programming well isn't.