What does mean "J-2" and where it comes from : "J-2 avant le contrôle ... " ?

Question

What does mean "J-2" and where it comes from : "J-2 avant le contrôle ... "  ?

Answer

J-2= "Jour J" - 2 jours

 "Jour J" is the french expression for "D Day", the day when something is expected to happen. If today is the "J-2" day, then the D day is the day after tomorrow.

J-2 avant le contrôle = In two days I'll have an exam