This is a pretty good catch you guys!
I already have a note to add a brief discussion of interrupt() to the next version of the study guide.
But I think the key thing to remember is that no one source will exactly cover exactly what might be on the exam. I know for instance that Kathy and I always try to cover about 110 - 115% of what we think is on the exam. I suspect other
SCJP authors also chose to over-prepare candidates with the study materials they create.
The other thing to remember is that when you go to take the exam, you will see only a small fraction of all the questions. So that isn't enough info to determine what might or might not be on another candidate's exam.
hth,
Bert