What is the difference between java.util.Collection and java.util.Collections?

java.util.Collection is the root interface of the collection hierarchy. It defines the basic operations available for all collections (adding, removing, checking for elements, etc.).

java.util.Collections is a utility class that contains static methods for performing various operations on collections (sorting, searching, changing order, creating unmodifiable views, etc.).

Here are the key differences in the form of a table:

Characteristic	java.util.Collection	java.util.Collections
Type	Interface	Class
Purpose	Defines the contract for collections	Provides utility methods
Usage	Implemented by collection classes	Used for manipulating collections
Object creation	No (interface)	Instances are not created (static methods)

Example of using Collections:

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

//
List<String> names = new ArrayList<>();
names.add("Bob");
names.add("Alice");
names.add("Charlie");

// Sorting the list
Collections.sort(names);

System.out.println(names); // Output: [Alice, Bob, Charlie]

// Creating an unmodifiable list
List<String> unmodifiableNames = Collections.unmodifiableList(names);
// unmodifiableNames.add("David"); // Will throw UnsupportedOperationException