"At the end of the 6 years as a junior FO (or whatever it is called) is there any guarantee that Jet* will retain your services as a full FO?"
So, after the 6 years are up and no guarantee of ongoing employment, Jetstar gives the former cadet the flick and recruits another new cadet; is that how it goes?
It would be much cheaper for Jetstar to do that, so why wouldn't they?
And the poor old ex-cadet goes out into the real world with his 6 years of "experience" looking for another job.......what are his chances?