J refers to the class on the aircraft.Y = EconomyJ = BusinessF = FirstThere are three categories for points tickets :Saver StandardFullA Business class ticket Brisbane to Singapore return may be available as :: Saver - for 90,000 pointsStandard - for 180,000 pointsFull - 426,000 pointsSame aircraft, same flight, different ticket restrictions.There are other ticket codes for all classes and a quick look on the web for "airline ticket codes"may interest you.It can become complex but tickets on points are related to "yield" to the airline. Singapore appear to have more availability of tickets on points (known as redemption tickets )than most.