It goes without saying that someone who will design an SCJP (Sun Certified Java Programmer) exam needs to be highly skilled not just in the basics of the Java programming language, but also its more advanced stages. You need someone who knows the theory inside out and also knows how it applies in real-world conditions.
Would you consider hiring someone who lacks high academic training but has extensive experience in applying Java in real-world conditions? That depends on whether the students and potential employers would find that acceptable. We all know that the great Bill Gates is not even a college graduate yet is a genius when it comes to computers, software- and hardware-wise. But to make him into a professional instructor, the training school would eventually wind up running into problems assuring students that he has the ability to impart what he knows in an academic learning environment.
When one takes an SCJP exam, it is usually assumed that knowledge and skills are standardized. The same is true with the Computer Science faculty that created the exam the students will assume that a standardized process of selecting such SCJP exam creators and administrators was used. Standardization has its critics, yet one cannot reject its value for giving everyone a common baseline from which to assume qualifications.
The best compromise is to get someone who does have higher levels of academic training but has also practiced the craft in a real-world company. Of special value would be a candidate who has worked for a start-up company since such fledgling businesses need more talent to stay alive than an established institution.