How to convience my father so that I can marry my boyfriend ?

My parents were very close and friendly since my childhood they gave me a lot of freedom to me they never objected me any thing like my friends, etc and even i use to tell them everything, and one more thing is their are very particular abt caste even, but i am in love with one of my classmate since five years they knew him as my friend but i revealed the Matter one year back it got delayed as my mother was passed but father not at all agreeing to my proposal , and the other side i like that guy but i don't like his parents at all even they don't like me, but he gives equal priority to both of us, but my dad dint expect this from me and tried a lot to make him agree his answer is always no, i don't want to go against him and though i love my bf i am not so confident . So pls suggest me wat to do

Frankly, your question is not very clear. You have not mentioned whether both of you are of same caste or not. And why your father oppose your relation. Further what about boy's family, are they ready to accept you?