Vector vs ArrayList in Java

Vector and ArrayList are dynamic array implementations in Java used to store elements that can grow or shrink in size. Both are part of the java.util package and provide indexed access to elements.

Both allow duplicate elements and maintain insertion order.
Both provide fast index-based access to elements.
They differ mainly in performance and thread-safety behavior.

ArrayList

ArrayList is a resizable array implementation of the List interface that allows dynamic storage of elements. It is widely used because it provides fast random access and flexible size management.

Maintains insertion order of elements.
Not synchronized, so it is not thread-safe.
Grows dynamically when elements are added.

Syntax:

List<DataType> listName = new ArrayList<>();

Java

import java.util.ArrayList;

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

        // Creating an ArrayList
        ArrayList<String> names = new ArrayList<>();

        // Adding elements
        names.add("Ravi");
        names.add("Aman");
        names.add("Neha");
        names.add("Priya");

        // Displaying ArrayList
        System.out.println("Names: " + names);

        // Accessing element using index
        System.out.println("Element at index 2: " + names.get(2));

        // Removing an element
        names.remove("Aman");

        // Updated ArrayList
        System.out.println("After removal: " + names);

        // Size of ArrayList
        System.out.println("Total Elements: " + names.size());
    }
}

Output

Names: [Ravi, Aman, Neha, Priya]
Element at index 2: Neha
After removal: [Ravi, Neha, Priya]
Total Elements: 3

Vector

Vector is a dynamic array implementation in Java that grows automatically when elements are added. It is similar to ArrayList but it is synchronized and thread-safe.

Vector is a legacy class introduced in Java 1.0 before the Collection Framework.
Maintains insertion order of elements.
Slower than ArrayList due to synchronization overhead..