List in Java: ArrayList and LinkedList

Introduction

In Java, the List interface is a part of the java.util package. Two commonly used implementations of the List interface are:

• ArrayList
• LinkedList

1. ArrayList

An ArrayList is a resizable array implementation of the List interface. It is best suited for scenarios where frequent access to elements is required.

Example: Using ArrayList

    import java.util.ArrayList;
    
    public class ArrayListExample {
        public static void main(String[] args) {
            // Create an ArrayList
            ArrayList list = new ArrayList<>();
    
            // Add elements to the ArrayList
            list.add("Apple");
            list.add("Banana");
            list.add("Cherry");
    
            // Display the ArrayList
            System.out.println("ArrayList: " + list);
    
            // Access an element by index
            System.out.println("Element at index 1: " + list.get(1));
    
            // Remove an element
            list.remove("Banana");
            System.out.println("After removal: " + list);
    
            // Iterate over the ArrayList
            System.out.println("Iterating through ArrayList:");
            for (String fruit : list) {
                System.out.println(fruit);
            }
        }
    }
        

2. LinkedList

A LinkedList is a doubly-linked list implementation of the List and Deque interfaces. It is best suited for scenarios where frequent insertions and deletions are required.

Example: Using LinkedList

    import java.util.LinkedList;
    
    public class LinkedListExample {
        public static void main(String[] args) {
            // Create a LinkedList
            LinkedList list = new LinkedList<>();
    
            // Add elements to the LinkedList
            list.add("Dog");
            list.add("Cat");
            list.add("Rabbit");
    
            // Display the LinkedList
            System.out.println("LinkedList: " + list);
    
            // Add an element at a specific index
            list.add(1, "Horse");
            System.out.println("After adding at index 1: " + list);
    
            // Remove an element by index
            list.remove(2);
            System.out.println("After removal: " + list);
    
            // Iterate over the LinkedList
            System.out.println("Iterating through LinkedList:");
            for (String animal : list) {
                System.out.println(animal);
            }
        }
    }
        

Differences Between ArrayList and LinkedList

Conclusion

Both ArrayList and LinkedList have their own strengths and weaknesses. Choose the one that best fits your application's requirements:

• Use ArrayList for faster random access and when memory is a concern.
• Use LinkedList for frequent insertions and deletions.