The mental hospital I can see - I've heard that before - but I don't know if I'd go from that to saying it was all fictitious. It seems too detailed to be fiction, and it never slips up and reveals itself to be potentially phony. (That raises the fun postmodern question of this being a story-within-a-story, but I don't think that was Salinger's intent at all.)
Of course, the fun thing about fiction that also doesn't get said enough is that the debating over what happened is part of the fun. I had one teacher who would present these analyses like they were hard fact, when in reality the only fact is what the author gives you, and the analyses can be debated with that in mind.
Of course, the fun thing about fiction that also doesn't get said enough is that the debating over what happened is part of the fun. I had one teacher who would present these analyses like they were hard fact, when in reality the only fact is what the author gives you, and the analyses can be debated with that in mind.