Java TreeSet - comparator() Method

The java.util.TreeSet.comparator() method returns the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements.

Syntax

public Comparator<? super E> comparator()

Here, E is the type of element maintained by the container.

Parameters

No parameter is required.

Return Value

Returns the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements.

Exception

NA.

Example:

In the example below, the java.util.TreeSet.comparator() method returns the comparator which returns null as the given set is already sorted according to the natural ordering system.

import java.util.*;

public class MyClass {
  public static void main(String[] args) {
    //creating a treeset
    TreeSet<Integer> MySet = new TreeSet<Integer>();

    //populating the set
    MySet.add(40);
    MySet.add(20);
    MySet.add(10);
    MySet.add(30);

    //printing the set
    System.out.println("MySet contains: " + MySet); 

    //creating comparator
    Comparator comp = MySet.comparator();
    
    //printing comparator value
    System.out.println("Comparator value is: "+ comp);  
  }
}

The output of the above code will be:

MySet contains: [10, 20, 30, 40]
Comparator value is: null