Dear student,

NTA would conduct the next JEE entrance in the last week of february probably then after every month they will complete their all four phases.

And if you want to appear for the NDA examination then you don't need to give the JEE mains exams of any session as you know that JEE is for the admission in engineering colleges but in NDA it is for the admission in National defense Academy for the 3 year training of Army, Navy, Airforce to become a officer in armed forces.

Good luck :)