Java Vector firstElement() Method

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Description

The Java Vector firstElement() method is used to return the first component (the item at index 0) of this vector.

Declaration

Following is the declaration for java.util.Vector.firstElement() method

public E firstElement()

Parameters

NA

Return Value

The method call returns the first component of this vector.

Exception

NoSuchElementException − This exception is returned if this vector has no components.

Getting first element of a Vector of Integer Example

The following example shows the usage of Java Vector firstElement() method to get an element at first position in this vector. We're creating a vector of Integer and added few elements to it using add() method. Then we've printed the element at index 0 using firstElement() method.

package com.tutorialspoint;

import java.util.Vector;

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

      // create an empty Vector vec with an initial capacity of 4      
      Vector<Integer> vec = new Vector<>(4);

      // use add() method to add elements in the vector
      vec.add(4);
      vec.add(3);
      vec.add(2);
      vec.add(1);

      // let us print the first element in the vector
      System.out.println("First element: "+vec.firstElement());
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

First element: 4

Getting first element of a Vector of String Example

The following example shows the usage of Java Vector firstElement() method to get first element in this vector. We're creating a vector of String and added few elements to it using add() method. Then we've printed the first element using firstElement() method.

package com.tutorialspoint;

import java.util.Vector;

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

      // create an empty Vector vec with an initial capacity of 4      
      Vector<String> vec = new Vector<>(4);

      // use add() method to add elements in the vector
      vec.add("D");
      vec.add("C");
      vec.add("B");
      vec.add("A");

      // let us print the first element in the vector
      System.out.println("First element: "+vec.firstElement());
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

First element: D

Getting first element of a Vector of Object Example

The following example shows the usage of Java Vector firstElement() method to get first element in this vector. We're creating a vector of Student and added few elements to it using add() method. Then we've printed the first element using firstElement() method.

package com.tutorialspoint;

import java.util.Vector;

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

      // create an empty Vector vec with an initial capacity of 4      
      Vector<Student> vec = new Vector<>(4);

      // use add() method to add elements in the vector
      vec.add(new Student(1, "Julie"));
      vec.add(new Student(2, "Robert"));
      vec.add(new Student(3, "Adam"));
      vec.add(new Student(4, "Jane"));	  

      // let us print the first element in the vector
      System.out.println("First element: "+vec.firstElement());
   }    
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
   
   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
}

Output

Let us compile and run the above program, this will produce the following result.

First element: [ 1, Julie ]