The problem is that each airline uses a specific set of codes for their own particular seat buckets. So J (full business class) on one airline may equate to C on another airline. Identify which airlines you are interested in and you will be more likely to get an answer - also check out some of the FAQs and stickys on the airline forums since this information is often held in there.

That said, since your question is off topic for Communitybuzz!, I'll move this thread over into Travelbuzz, where others will be able to chime in.

Jenbel
Co-moderator, Communitybuzz!