Object:
If we see this world with perspective of OOPs, Every thing in this world is treated as object. With OOPs we get power to create Objects of our own and use them according to the need.
Class:
A Class is abstract model which defines a new abstract data type in a programming language, so that we can re-use abstract data type with the help of objects that are instance of class.
Interface:
An interface is a prototype for classes that will implement it and it help them with logical design perspective. Interfaces defines protocols for a class without worrying about the implementation details.