Sri Jayawardenepura Kotte, commonly known as Kotte (/ˈkoʊteɪ/), is the official, administrative capital of Sri Lanka. It seems ridiculous but the capital is just a suburban area of the largest city of Sri-Lanka. That's why some people may think of Colombo as the right answer.

Since 1982 the Parliament of Sri-Lanka has been situated in Kotte. The buildings of the Parliament are placed in the center of the lake. At present, all the other legislative institutions of the country are gradually relocating from the previous capital to the new one.

More Info: en.wikipedia.org