Java LinkedList removeFirst() method
Syntax and Examples

Introduction

The removeFirst() method in Java's LinkedList class is a handy way to remove and return the element at the head (beginning) of the list. Think of it like taking the first item off a stack or grabbing the front car from a line of traffic.

Syntax

    
    public E removeFirst()
    
  

Parameters

Parameter	Description
None	This method doesn't take any parameters. It simply removes the first element of the list.

Return Value

The removeFirst() method returns the element that was removed from the head of the list. If the list is empty, it throws a NoSuchElementException.

Examples

Example 1: Removing the First Element

This example demonstrates how to remove and retrieve the first element from a LinkedList.

    
    import java.util.*;

    public class RemoveFirstExample {
        public static void main(String[] args) {
            LinkedList<String> myList = new LinkedList<>(
                Arrays.asList("Apple", "Banana", "Cherry")
            );

            System.out.println("Original list: " + myList);

            String firstElement = myList.removeFirst();

            System.out.println("Removed element: " + firstElement);
            System.out.println("List after removal: " + myList);
        }
    }
    
  

Original list: [Apple, Banana, Cherry]
Removed element: Apple
List after removal: [Banana, Cherry]

Explanation: We create a LinkedList containing strings. removeFirst() removes “Apple” (the first element) and returns it. The original list is then modified to exclude the removed element.

Example 2: Handling an Empty List

This example shows what happens when you try to remove the first element from an empty LinkedList.

    
    import java.util.*;

    public class RemoveFirstEmptyExample {
        public static void main(String[] args) {
            LinkedList<Integer> emptyList = new LinkedList<>();

            try {
                Integer firstElement = emptyList.removeFirst();
                System.out.println("Removed element: " + firstElement);
            } catch (NoSuchElementException e) {
                System.out.println("Error: List is empty, cannot remove the first element.");
            }
        }
    }
    
  

Error: List is empty, cannot remove the first element.

Explanation: Because emptyList is initialized as an empty LinkedList, attempting to call removeFirst() results in a NoSuchElementException. The try-catch block handles this exception gracefully.

Example 3: Removing from a List of Integers

This example demonstrates removing the first element from LinkedList containing Integer objects.

    
    import java.util.*;

    public class RemoveFirstIntegerExample {
        public static void main(String[] args) {
            LinkedList<Integer> numbers = new LinkedList<>(Arrays.asList(10, 20, 30));

            System.out.println("Original list: " + numbers);

            Integer firstNumber = numbers.removeFirst();

            System.out.println("Removed element: " + firstNumber);
            System.out.println("List after removal: " + numbers);
        }
    }
    
  

Original list: [10, 20, 30]
Removed element: 10
List after removal: [20, 30]

Explanation: A LinkedList of Integer objects is created. The first element (10) is removed and returned by the removeFirst() method.