Java Vector capacity() Method

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Description

The Java Vector capacity() method is used to return the current capacity of a vector.Capacity is the length of the array kept in the vactor.

Declaration

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

public int capacity()

Parameters

• This method does not take any parameter as input.

Return Value

The method returns the current capacity of the vector as an integer value.Here capacity means the length of its internal data array, kept in the field elementData of this vector.

Exception

NA

Getting Capacity of a Vector of Integer Example

The following example shows the usage of Java Vector capacity() method to get the capacity of the vector. We're adding couple of Integers to the Vector object using add() method calls per element and then print the vector capacity.

package com.tutorialspoint;

import java.util.Vector;

public class VectorDemo {
   public static void main(String[] args) {
      
      // create an empty array list 
      Vector<Integer> vector = new Vector<>();

      // use add() method to add elements in the vector
      vector.add(20);
      vector.add(30);
      vector.add(20);
      vector.add(30);
      vector.add(15);
      vector.add(22);
      vector.add(11);

      System.out.println("Vector capacity: " + vector.capacity());
   }
}

Output

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

Vector capacity: 10

Getting Capacity of a Vector of String Example

The following example shows the usage of Java Vector capacity() method to get the capacity of the vector. We're adding couple of Strings to the Vector object using add() method calls per element and then print the vector capacity.

package com.tutorialspoint;

import java.util.Vector;

public class VectorDemo {
   public static void main(String[] args) {
      
      // create an empty array list
      Vector<String> vector = new Vector<>();

      // use add() method to add elements in the vector
      vector.add("Welcome");
      vector.add("To");
      vector.add("Tutorialspoint");
      System.out.println("Vector capacity: " + vector.capacity());      
   }
}

Output

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

Vector capacity: 10

Getting Capacity of a Vector of an Object Example

The following example shows the usage of Java Vector capacity() method to get the capacity of the vector. We're adding couple of Student objects to the Vector object using add() method calls per element and then print the vector capacity.

package com.tutorialspoint;

import java.util.Vector;

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

      // create an empty vector
      Vector<Student> vector = new Vector<>();

      // use add() method to add elements in the vector
      vector.add(new Student(1, "Julie"));
      vector.add(new Student(2, "Robert"));
      vector.add(new Student(3, "Adam"));
      System.out.println("Vector capacity: " + vector.capacity());      
   }
}

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 + " ]";
   }
}

Output

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

Vector capacity: 10