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Java Program to Add elements to a LinkedList

In this example, we will learn to insert elements to the Java LinkedList using various methods.

To understand this example, you should have the knowledge of the following Java programming topics:


Example 1: Add Elements Using add()

import java.util.LinkedList;

class Main {
  public static void main(String[] args){

    // create a linkedlist
    LinkedList<String> languages = new LinkedList<>();

    // Add elements to LinkedList
    languages.add("Java");
    languages.add("Python");
    languages.add("JavaScript");
    System.out.println("LinkedList: " + languages);
  }
}

Output

LinkedList: [Java, Python, JavaScript]

Here, the add() method inserts an element at the end of a linkedlist. However, we can also insert elements at the specified position using the add() method.

Example 2: Add element at the specified position

import java.util.LinkedList;

class Main {
  public static void main(String[] args){

    // create a linkedlist
    LinkedList<String> languages = new LinkedList<>();

    // add elements to LinkedList
    languages.add("Swift");
    languages.add("Python");
    System.out.println("LinkedList: " + languages);

    // add element at the specified position
    languages.add(0, "Java");
    System.out.println("Updated LinkedList: " + languages);
  }
}

Output

LinkedList: [Swift, Python]
Updated LinkedList: [Java, Swift, Python]

In the example, notice the line,

languages.add(0, "Java");

Here, 0 is an optional parameter that specifies the index number where the new element is to be added.


Example 3: All all elements from other collection to LinkedList

To add all the elements of a collection to another linked list, we use the addAll() method.

import java.util.LinkedList;

class Main {
  public static void main(String[] args) {
    LinkedList<String> mammals = new LinkedList<>();

    mammals.add("Dog");
    mammals.add("Cat");
    mammals.add("Horse");
    System.out.println("Mammals: " + mammals);

    LinkedList<String> animals = new LinkedList<>();
    animals.add("Crocodile");

    // Add all elements of mammals in animals
    animals.addAll(mammals);
    System.out.println("Animals: " + animals);
  }
}

Output

Mammals: [Dog, Cat, Horse]
Animals: [Crocodile, Dog, Cat, Horse]

Example 4: Using listIterator() method

We can also use the listsIterator() method to add elements to the linked list. To use it, we must import java.util.ListIterator package.

import java.util.ArrayList;
import java.util.ListIterator;

class Main {
  public static void main(String[] args) {
    ArrayList<String> languages = new ArrayList<>();

    // Creating an object of ListIterator
    ListIterator<String> listIterate = languages.listIterator();
    listIterate.add("Java");
    listIterate.add("Python");

    System.out.println("LinkedList: " + languages);
  }
}

Output

LinkedList: [Java, Python]