Vector firstElement() Method in Java

The java.util.vector.firstElement() method in Java is used to retrieve or fetch the first element of the Vector. It returns the element present at the 0^th index of the vector 

Syntax:

Vector.firstElement()

Parameters: The method does not take any parameter. 

Return Value: The method returns the first element present in the Vector. Below programs illustrate the Java.util.Vector.firstElement() method: 

Program 1:

Java

// Java code to illustrate firstElement()
import java.util.*;

public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector<String> vec_tor = new Vector<String>();

        // Use add() method to add elements into the Vector
        vec_tor.add("Welcome");
        vec_tor.add("To");
        vec_tor.add("Geeks");
        vec_tor.add("4");
        vec_tor.add("Geeks");

        // Displaying the Vector
        System.out.println("Vector: " + vec_tor);

        // Displaying the first element
        System.out.println("The first element is: "
                           + vec_tor.firstElement());
    }
}

Output:

Vector: [Welcome, To, Geeks, 4, Geeks]
The first element is: Welcome

Program 2:

Java

// Java code to illustrate firstElement()
import java.util.*;

public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector<Integer> vec_tor = new Vector<Integer>();

        // Use add() method to add elements into the Vector
        vec_tor.add(10);
        vec_tor.add(15);
        vec_tor.add(30);
        vec_tor.add(20);
        vec_tor.add(5);

        // Displaying the Vector
        System.out.println("Vector: " + vec_tor);

        // Displaying the first element
        System.out.println("The first element is: "
                           + vec_tor.firstElement());
    }
}

Output:

Vector: [10, 15, 30, 20, 5]
The first element is: 10

Time complexity: O(1). 
Auxiliary Space: O(n). // n is the size of the vector.