Convert Vector to ArrayList in Java

There are multiple ways to convert vector to ArrayList, using passing the Vector in ArrayList constructor and by using simple vector traversal and adding values to ArrayList.

Approach 1:

1. Create a Vector.
2. Add some values in Vector.
3. Create a new ArrayList.
4. Traverse vector from the left side to the right side.
5. Start adding each element in ArrayList.

Below is the implementation of the above approach:

Java

// Convert Vector to ArrayList in Java
import java.util.Vector;
import java.util.ArrayList;

public class GFG {

    public static void main(String[] args)
    {

        // Create a Vector that contain strings

        Vector<String> v = new Vector<String>();

        // add values in vector

        v.add("a");
        v.add("b");
        v.add("c");
        v.add("d");
        v.add("e");

        // Display the Vector

        System.out.println(" Vector :  " + v);

        ArrayList<String> Arrlist = new ArrayList<String>();

        // Convert Vector to ArrayList
        for (int i = 0; i < v.size(); i++)
            Arrlist.add(v.get(i));
        // Display ArrayList
        System.out.println("\n ArrayList : " + Arrlist);
    }
}

Time Complexity: O(n)

Approach 2:

• Create a Vector.
• Add some values in Vector.
• Create an ArrayList and pass the Vector in ArrayList Constructor.

Syntax:

ArrayList<String> ArrList = new ArrayList<String>(vector);

Below is the implementation of the above approach:

Java

// Convert Vector to ArrayList in Java
import java.util.Vector;
import java.util.ArrayList;

public class GFG {

    public static void main(String[] args)
    {

        // Create a Vector that contain strings

        Vector<String> v = new Vector<String>();

        // add values in vector

        v.add("a");
        v.add("b");
        v.add("c");
        v.add("d");
        v.add("e");

        // Display the Vector

        System.out.println(" Vector :  " + v);

        // Convert Vector to ArrayList
        ArrayList<String> Arrlist
            = new ArrayList<String>(v);

        // Display ArrayList
        System.out.println("\n ArrayList : " + Arrlist);
    }
}

Output

 Vector :  [a, b, c, d, e]

 ArrayList : [a, b, c, d, e]

Time Complexity: O(n)

Approach 3 : Using addAll()

1. Declare and Initialize the Vector object with values.
2. Now, declare the ArrayList.
3. By using addAll() method, we can simply add all elements from Vector to ArrayList. Declare the vector object in the addAll() method i.e ArrayList_object.addAll(Vector_object).
4. Print the ArrayList.

Java

// Java Program to Convert Vector to ArrayList

import java.util.ArrayList;
import java.util.Vector;

public class GFG {

    public static void main(String[] args)
    {
        // Create a Vector that contain strings
        Vector<String> v = new Vector<String>();

        // add values in vector

        v.add("a");
        v.add("b");
        v.add("c");
        v.add("d");
        v.add("e");

        // Display the Vector
        System.out.println(" Vector :  " + v);

        // Converting vector to ArrayList
        ArrayList<String> Arrlist = new ArrayList<String>();
        Arrlist.addAll(v);

        // Displaying the above ArrayList
        System.out.println("\n ArrayList : " + Arrlist);
    }
}

Output

 Vector :  [a, b, c, d, e]

 ArrayList : [a, b, c, d, e]