In which design pattern is the Comparator class used for comparing objects?

The Comparator class in Java is used in the Strategy design pattern.

Comparator implements an interface that defines a comparison strategy for objects. This allows changing the comparison method without modifying the classes of the objects themselves.

For example, if you have a list of objects and want to sort them by different criteria, you can create different Comparator implementations and pass them to sorting methods:

List<Person> people = ...;

// Sorting by name
Comparator<Person> byName = (p1, p2) -> p1.getName().compareTo(p2.getName());

// Sorting by age
Comparator<Person> byAge = Comparator.comparingInt(Person::getAge);

Collections.sort(people, byName);
Collections.sort(people, byAge);

Thus, Comparator allows flexible changing of the comparison algorithm, which corresponds to the Strategy pattern.