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You will be considered a resident in 2020 since you met the Substantial Presence Test.

As a J-1 visa holder, you are considered as a nonresident for two years from the first year you enter the US.  In your case, you were a nonresident in 2014-2015.

"You will not be an exempt individual as a teacher or trainee if you were exempt as a teacher, trainee, or student for any part of 2 of the 6 calendar years preceding the current year."(IRS Exempt Individuals: Teachers and Trainees)