What is the LinkedList.removeFirst method in Java?

What is the removeFirst method of the LinkedList class?

The removeFirst method can be used to remove the first element of the linked list.

Linked list

A linked list is a collection of linear data elements. Each element, or node, contains data and reference parts.

• The data part has the value
• The reference part has the address to the next element

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

In Java, the LinkedList is a doubly-linked listA kind 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.

Syntax

public E removeFirst();

This method doesn’t take any arguments. It removes and returns the first element of the list. If the list is empty then the NoSuchElementException exception is thrown.

Code

The code below demonstrates how to use the removeFirst 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<>();

• In 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 removeFirst method of the list object to remove the first element of the list. This method removes the first element of the list and returns the removed element.

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