11:07 AM PT -- 6/2 -- Cole Buckley -- the 21-year-old fan who allegedly threw a water bottle at Kyrie Irving -- appeared at Boston Municipal Court on Wednesday for his arraignment ... and was ordered to stay away from the TD Garden.
Buckley entered a not guilty plea for assault and battery with a dangerous weapon ... and was silent as he left the courthouse.
Suffolk County DA Rachael Rollins spoke with reporters about the case ... saying, "It is not lost on me that he chose to do this in a sport that is overwhelmingly Black men," according to reporter Juliana Mazza.