Main differences between Collection and Collections are as
follows:
1. Collection is an interface in Java. But Collections is a
class in Java.
2. Collection is a base interface. Collections is a utility class
in Java.
3. Collection defines methods that are used for data structures
that contain the objects. Collections defines the methods
that are used for operations like access, find etc. on a
Collection
https://www.geeksforgeeks.org/collection-vs-collections-in-java-with-example/