There's a difference between being fluent in something and mastering it. You might be capable of reading and writing Java code, but that says nothing of your k

There's a difference between being fluent in something and mastering it. You might be capable of reading and writing Java code, but that says nothing of your knowledge of JVM internals or of any particular framework etc. It's like the difference between being fluent in Spanish and being able to use the language to write moving poetry or having a very extensive vocabulary. I think it is much better to be as specific as possible about what skills you expect the candidate to have going in and what you expect them to be able to learn on the job.