Java LinkedList removeFirstOccurrence() method
Syntax and Examples

Introduction

The removeFirstOccurrence() method in Java's LinkedList class provides a way to remove the first instance of a specified object from the list. Unlike remove() which removes the *first* element matching an index, this method finds and removes only the initial occurrence of the target object.

Syntax

public boolean removeFirstOccurrence(Object o)

Parameters

Parameter	Description
o	The object to be removed from the list. If the list does not contain the specified object, this method returns false.

Return Value

This method returns true if the object was found and removed; otherwise, it returns false.

Examples

Example 1: Removing a String

Let's see how to remove the first occurrence of a specific string from a LinkedList.

import java.util.LinkedList; 
 public class RemoveFirstOccurrenceExample {
    public static void main(String[] args) {
        LinkedList<String> myList = new LinkedList<>();
        myList.add("apple");
        myList.add("banana");
        myList.add("orange");
        myList.add("banana");

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

        boolean removed = myList.removeFirstOccurrence("banana");

        System.out.println("List after removing first 'banana': " + myList);
        System.out.println("Was the element removed? " + removed);
    }
}

Original list: [apple, banana, orange, banana] 
List after removing first 'banana': [apple, orange, banana] 
Was the element removed? true

In this example, we create a LinkedList of strings. We then call removeFirstOccurrence("banana"). The list is modified to remove only the *first* instance of "banana". The method returns true because “banana” was present and removed.

Example 2: Removing an Integer

This example demonstrates removing the first occurrence of an integer from a LinkedList.

import java.util.LinkedList; 
 public class RemoveFirstOccurrenceIntegerExample {
    public static void main(String[] args) {
        LinkedList<Integer> myList = new LinkedList<>();
        myList.add(10);
        myList.add(20);
        myList.add(30);
        myList.add(20);

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

        boolean removed = myList.removeFirstOccurrence(20);

        System.out.println("List after removing first 20: " + myList);
        System.out.println("Was the element removed? " + removed);
    }
}

Original list: [10, 20, 30, 20] 
List after removing first 20: [10, 30, 20] 
Was the element removed? true

Here, we create a LinkedList of Integers and remove the first occurrence of the integer 20. The method correctly removes only the initial '20'. The returned value is true indicating successful removal.

Example 3: Object Not Found

This example shows what happens when you try to remove an object that doesn't exist in the list.

import java.util.LinkedList; 
 public class RemoveFirstOccurrenceNotFoundExample {
    public static void main(String[] args) {
        LinkedList<String> myList = new LinkedList<>();
        myList.add("apple");
        myList.add("banana");

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

        boolean removed = myList.removeFirstOccurrence("grape"); 

        System.out.println("List after attempting to remove 'grape': " + myList);
        System.out.println("Was the element removed? " + removed);
    }
}

Original list: [apple, banana] 
List after attempting to remove 'grape': [apple, banana] 
Was the element removed? false

In this case, we attempt to remove “grape”, which isn't present in the LinkedList. The list remains unchanged, and removeFirstOccurrence() returns false.