What is the LinkedList.pollFirst() method in Java?

What is LinkedList?

A linked list is a collection of linear data elements. Each element (node) contains data and reference parts. The data part has the value and the reference part has the address link to the next element.

The elements are not indexed so random access like in Array objects is not possible. Instead, we traverse from the beginning of the list and access the elements.

In Java, the LinkedList class is a doubly-linked listKind of linked list. Each node contains three fields: two link fields (one for the previous element and another for the next element) and one data field. implementation of the List and Deque interfaces. The LinkedList class is present in the java.util package.

What is the pollFirst() method of the LinkedList class?

The pollFirst() method can be used to get and remove the first element of a LinkedList object.

Syntax

The syntax of the pollFirst() method is as follows.

public E pollFirst();

This method doesn’t take any arguments.

This method retrieves and removes the first element of the specified LinkedList. If the list is empty. then null is returned.

Code

The code below demonstrates how to use the pollFirst() method.

Explanation

In the code above:

• In line 1, we imported the LinkedList class.

import java.util.LinkedList;

• In line 4, we created a LinkedList object with the name list.

LinkedList<String> list = new LinkedList<>();

• From lines 5 to 7, we used the add() method of the list object to add three elements ("1","2","3") to the list.

list.add("1");
list.add("2");
list.add("3");

• In line 10, we used the pollFirst() method of the list object to get and remove the first element.

list.pollFirst(); // "1"
list; // ["2", "3"]