What is the difference between Collection and Collections in java?

Answer 1

Collection is an interface whereas Collections is a class. Collection interface provides normal functionality of data structure to List, Set and Queue. But, Collections class is to sort and synchronize collection elements.

Answer 2

Collections is merely an utility method class for doing certain operations, for example adding thread safety to your ArrayList instance by doing this.

List<Object> list = Collections.synchronizedList(new Arraylist<Object>());

The main difference in my opinion is that Collection is base interface which you may use in your code as a type for object while Collections just provides useful operations for handling the collections.