It is the root interface in the collection hierarchy.
It represents a group of individual objects as a single entity.
Most of the classes in Java Collection Framework inherit from this interface. List, Set and Queue are main sub interfaces of this interface.
Map interface, which is also a part of java collection framework, doesn’t inherit from Collection interface.
JDK doesn’t provide any direct implementations of this interface. But, JDK provides direct implementations of it’s sub interfaces. ArrayList, Vector, HashSet, LinkedHashSet, PriorityQueue are some indirect implementations of Collection interface.
Collection interface is a member of java.util package.
Collections
Collections is an utility class in java.util package.
It consists of only static methods (like sorting, searching, etc.) which are used to operate on Collection objects.
Some important methods of Collections class are Collections.max(), Collections.min(), Collections.sort()
