The roster includes seven events: five concerts, plus a boxing event and the 2014 NBA draft.
(As noted by @NetsDaily's Bob Windrem, the 10,000 expected for the 2014 draft is twice that last year, though neither New York team has a pick. This year tickets are $15/$20/$35, while last year they were $20/$35. I'm not sure that pricing will get them to 10,000 people. There might have to be some giveaways.)
Though the arena can seat up to 19,000 for concerts, the largest crowd expected is for Avicii, a Swedish DJ, remixer, and record producer, with an estimated attendance of 13,000. Some of his output is classified as electronic dance music (EDM), the genre that has sometimes led to loud bass leaking from the Barclays Center into neighbors' homes.
The calendar does not list events without public ticketing, so it ignores things like graduations or the recent Falun Gong conference.
Long Island University held its commencement at the arena yesterday. NYU/Polytechnic will hold its commencement May 23. CUNY's Medgar Evers College--the only new entrant in the list, as far as I know--will have its ceremony May 31. Brooklyn Tech High School will hold its graduation ceremony at the arena on June 15.
By contrast, the June 2013 event calendar listed nine events in 30 days.