Brooklyn went from zero to two professional sports franchises in the time it takes to say, “Junior’s cheesecake.” The NHL’s New York Islanders followed the Nets, formerly of New Jersey, to the sprawling new Barclays Center in downtown Brooklyn, it was announced Wednesday.The Islanders, who played in Hemstead on Long Island, have a 25-year, “iron-clad” agreement to play in the Barclays Center in Brooklyn, owner Charles Wang said.The Islanders will begin playing in Brooklyn at the beginning of the 2015-16 season, when their current lease with the archaic Nassau Coliseum expires.“It was our goal from day one to keep the Islanders in the local New York area.” Wang said in a team statement. “We’re thrilled to have the opportunity to play in Barclays Center, a first class arena. This has been a long journey for the Islanders family starting with our loyal fans, sponsors, and employees. I want to personally thank them for their patience, loyalty and support. I am excited about today’s announcement, and I am looking forward to a long and successful future in Brooklyn.”The press conference was attended by everyone from Wang, to New York mayor Michael Bloomberg, to NHL commissioner Gary Bettman, to Brooklyn borough president Marty Markowitz.“Today is another great day for Brooklyn,” Markowitz said. “When I first campaigned for borough president, I made the promise that I would bring a major league sports team to Brooklyn. But never in my wildest dreams did I think we would be home to both the Brooklyn Nets and the New York Islanders.Barclays Center majority owner Bruce Ratner was also in attendance. As recently as August, Ratner said he was “trying like hell” to get the Islanders to join the Nets in Brooklyn.In making the move of about 25 miles west, the Islanders will be rejoining the Nets. The Nassau Coliseum opened in 1972 as home to both the expansion Islanders and the New York Nets of the American Basketball Association. The Nets moved to New Jersey in 1977, one year after joining the NBA.The Barclays Center will hold an estimated 14,500 fans for hockey, which will make it the smallest arena in the NHL. The MTS Centre in Winnipeg is the smallest, with a capacity of 15,004. The Islanders averaged just 13,191 last season and haven’t had an average of more than 14,000 since the 2002-03 season.Bettman said he didn’t think the number of seats would be an issue and pointed out the “intimacy” of the building.