Why is NJ taxing my IRA ROTH distribution even though it is only the contribution that is being withdrawn? There were no earnings. My 1099-R has code J.

NJ treats distributions from Roth accounts with code J or T as taxable. 

Once you go back in to the NJ return Select Go Over NJ Again 

You will get to the Roth Distribution For You page. Hit Continue

If this is the first year of withdrawal you get this pop out. All your Roth Contributions are previously taxed