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Java TreeSet comparator() Method with Example

TreeSet Class comparator() method: Here, we are going to learn about the comparator() method of TreeSet Class with its syntax and example.
Submitted by Preeti Jain, on February 20, 2020

TreeSet Class comparator() method

• comparator() method is available in java.util package.
• comparator() method is used to get the Comparator object based on customizing order the elements in this TreeSet.
• comparator() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• comparator() method does not throw an exception at the time of returning the Comparator object.

Syntax:

    public Comparator comparator();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Comparator, it gets Comparator based on defining the order of elements in this TreeSet otherwise it returns null when this TreeSet follows defalult ordering its elements.

Example:

// Java program to demonstrate the example 
// of Comparator comparator() method of TreeSet 

import java.util.*;

public class ComparatorOfTreeSet {
    public static void main(String[] args) {
        // Instantiates a TreeSet object
        TreeSet < String > tree_set = new TreeSet < String > ();

        // By using add() method is to add
        // the given object of this TreeSet 
        tree_set.add("C");
        tree_set.add("C++");
        tree_set.add("JAVA");
        tree_set.add("PHP");
        tree_set.add("SFDC");

        // Display TreeSet
        System.out.println("TreeSet: " + tree_set);

        // By using comparator() method is to return
        // the Comparator 
        Comparator com = tree_set.comparator();

        // Display Comparator
        System.out.println("tree_set.comparator(): " + com);
    }
}

Output

TreeSet: [C, C++, JAVA, PHP, SFDC]
tree_set.comparator(): null