Difference between UX Designer and UI Developer

UX Designer - User experience designer

UI Developer - User Interface Developer

Consider a customer ordered cup of tea.

How the tea cup should be? What must be filled in cup?

UX designer has the answer for the above questions.

UX Designer decides the shape of the cup.Design it's holder.And fill it with Milk & Tea power(dark/light shade).

It is not in usable mode now. That is customer cann't drink it now. So how it should be made as usable to customer(who ordered tea) ?????

UI Developer has the answer for the above questions.

UI developer place a spoon inside a cup of tea. 

Decides whether to add sugar/lemon anything based on the input from the customer.Mix it well and finally tasteful usable tea is ready for the customer to drink.

Conclusion:

 In a website, what are all design elements to be added will be decided and designed by UX designer and how the designed elements should interact with each other to make it user friendly is decided and devloped by UI developer.