TreeSet pollLast() method in Java with Example

The pollLast() method of Java.util.concurrent.TreeSet is an in-built function in Java which returns retrieves and removes the last (highest) element, or returns null if this set is empty.

Syntax:

public E pollLast()

Return Value: The function returns retrieves and removes the last (highest) element, or returns null if this set is empty.

Below programs illustrate the TreeSet.pollLast() method:

Program 1:

// Java program to demonstrate pollLast()
// method of TreeSet

import java.util.*;

class TreeSetpollLastExample1 {
    public static void main(String[] args)
    {
        // Creating a set object
        TreeSet<Integer> set
            = new TreeSet<Integer>();

        // Adding elements to this set
        for (int i = 10; i <= 50; i += 10)
            set.add(i);

        // Printing the content of the set
        System.out.println("Contents of the set: " + set);

        // Retrieving and removing Last element of the set
        System.out.println("The Last element of the set: "
                           + set.pollLast());

        // Printing the content of the set after pollLast()
        System.out.println("Contents of the set after pollLast: "
                           + set);
    }
}

Output:

Contents of the set: [10, 20, 30, 40, 50]
The Last element of the set: 50
Contents of the set after pollLast: [10, 20, 30, 40]

Program 2:

// Java program to demonstrate pollLast()
// method of TreeSet

import java.util.*;

class TreeSetpollLastExample2 {
    public static void main(String[] args)
    {
        // Creating a set object
        TreeSet<Integer> set
            = new TreeSet<Integer>();

        // Printing the content of the set
        System.out.println("Contents of the set: "
                           + set);

        // Retrieving and removing Last element of the set
        System.out.println("The Last element of the set: "
                           + set.pollLast());
    }
}

Output:

Contents of the set: []
The Last element of the set: null