Mostly Tamils mixed with some Muslims and Buddhists. It's a wonderful place to retreat for a while. There is many Tea estates around and one can walk virtually for several weeks, without ever taking the same path twice. As it is located on top of a mountain range, the views are exceptional. Though being quite high above sea level, the sun should be minded.
Get in By rail. Haputale is halfway Nanu Oya and Badulla, towards the end of the railway line that snakes through the Hill Country. Trains go to Colombo and Kandy from here. The fares are ludicrously cheap in 2nd and 3rd class and the views spectacular. It's usually no problem getting a seat in 2nd/3rd class going to Colombo or Kandy, as the trains from Badulla are quite empty until reaching Nanu Oya. However the reverse is true going up to Haputale and it can be quite crowded until the last 2 or 3 hours of the journey By Road. Haputale is on the direct route 99 Colombo-Ratnapura-Bandarawela-Badulla. For southbound connections, take bus 99 in direction of Ratnapura and exit at Pelmadulla; here you can take buses to Uda Walawe, Embilipitiya and onwards the south coast.
Walking or by rickshaw, as usual in Sri Lanka. One can also take the train to visit smaller places around Haputale (the also tiny places Ella, Bandarawella or Badulla, for example). It's also quite common to take the train to one of the neighboring villages and simply walk back that same way on the rail tracks. It's totally normal in Sri Lanka to walk on rail tracks. Trains are slow and using their horn more than permanently. Those rail track walks offer one of the best views Sri Lanka has to offer.