I did a few internships in college. I interviewed with Microsoft. They looked at my resume, code samples I gave them (in C++, Python and PHP), and ran through a phone interview where I solved some problems over the phone in pseudocode. They hired me into a product team as a C#.NET software developer with no experience in C#, .NET or Windows programming. I learned the syntax and libraries on the job and was solving bugs on the second day.
I'm pretty bad at analogies, but this is the best I've got: You want to hire a mechanic. You're a Ford dealer. You're refusing to hire young, trained and certified mechanics because they can't tell you about a specific quirk of the 2009 Ford Escape brake assembly. They weren't trained with Ford-specific knowledge, and they'd figure out the brake thing within 20 minutes of seeing it, but you're balking that these mechanics applied to a Ford dealer without that Ford knowledge.
Exceptions are not some obscure, theoretical language construct and Java exceptions aren't an arcane, experts-only part of the language. If I'm hiring for a "Jr. Java Developer", I expect them to know Java. Not every detail, not the edge cases, the really weird stuff, the 3rd party libraries, the frameworks. But they should know the core language features and syntax. If he's told me he knows Java, and I have to give him a pass on exceptions, is it cool if he can't create a derived class? Doesn't know the type system? Operator precedence? How little competence is okay?
I have an expectation that if you are applying for a "Jr. Java Developer", no matter what you did or did not learn in school, you'd better have picked up a book or cranked up Google and gotten familiar with Java. Why? Because as a programmer, that's going to be the rest of your career. Good programmers are always going to need to be learning something new, often quickly, and usually doing it on their own. If you aren't willing to do that to get the job, why would I expect you to do it once you have the job. And if you can't pick up a passing level of competence in the core language features in a couple of days of prep, then you probably don't need to be working in programming.
Unless it's Lisp. Totally cool if it takes months to wrap your brain around that.