I would venture to guess that you have not done much hiring and, thus, have not been burned by taking on developers, spending time and money to get them up to speed on application architecture, domain knowledge, and team processes, only to find out that they don't know how to write code.

A developer that cannot take basic requirements and codify them into working software is not a developer. A logician, scientist, or mathematician, maybe, but not a developer. And our hiring process is designed to help distinguish the developers from the non-developers.

That's what you think your hiring process is designed to do. Instead it's screening for particular pieces of trivia instead of knowledge and competency. It's only going to get worse as vanilla Java becomes more and more relegated to maintenance of old codebases. It's not a language most CS programs use to teach at this point.

You can test whether someone can turn requirements into working code without testing for specific bits of trivia. Simply saying "solve this in the language you're most comfortable with" does away with that flaw in your process, while still allowing you to see whether they can code, whether they write tests, whether they think of edge/corner cases, whether they handle errors or malformed inputs, how they think about problem solving, etc.

There are plenty of companies that hire developers without finding out they hired people who can't code only after investing in them. They don't do it by adding language trivia to the interviews. If it's too difficult for you, you can outsource that part: https://www.interviewstreet.com/recruit2/