What is the LinkedList.removeFirstOccurrence method in Java?

LinkedList

A LinkedList is a collection of linear data elements. Each element, or node, contains a data part and a reference part.

The data part has the value and 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 the doubly-linked list implementation of the List and Deque interfaces.

The LinkedList class is present in the java.util package.

What is the removeFirstOccurrence method of the LinkedList class?

The removeFirstOccurrence method is used to remove the first occurrence of the specified element in the LinkedList.

Syntax

public boolean removeFirstOccurrence(Object o);

Parameter

This method takes the element to be removed from the list as a parameter.

Return value

This method returns true if the list contains the specified element. Otherwise, it returns false.

Code

The code below demonstrates how to use the removeFirstOccurrence method.

import java.util.LinkedList;
class LinkedListRemoveFirstOccurrenceExample {
    public static void main( String args[] ) {
      LinkedList<String> list = new LinkedList<>();
      list.add("1");
      list.add("2");
      list.add("1");
      System.out.println("The list is " + list);
      
      System.out.println("Is element present " + list.removeFirstOccurrence("1"));
      System.out.println("The list is " + list);
    }
}

Explanation

In the above code:

  • In line number 1, we import the LinkedList class.
import java.util.LinkedList;
  • In line number 4, we create a LinkedList objects with the name list.
LinkedList<String> list = new LinkedList<>();
  • From line number 5 to 7, we use 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 number 10, we use the removeFirstOccurrence method to remove the first occurrence of the element "1". The element "1" is present in two indexes, 0 and 2. After calling this method, the element at index 0 will be removed.
list.removeFirstOccurrence("1"); // true

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