Im nebbies on elliptic curve cryptography and i need help to understand if i did good work : i use

Java and bouncycastle and i must to generate public and private key from Ecc curve . I take 3 different kind of code from web , but im not sure which is the best . I read that the curve must generate in RANDOM mode for security , but i dont understand how

I've some question :

1)which of this code is the most secure and why?

2)what is the meaning of this :" 192 bit ecc is like 2048 bit rsa"? which is the size of private and public key in Ecc prime192v1? and in another? why?

3)how generate random curve ?how can generate random private and public key?

can anyone help me?

thanks so much

thanks