Home » Java programming language

Java Vector retainAll() Method with Example

Vector Class retainAll() method: Here, we are going to learn about the retainAll() method of Vector Class with its syntax and example.
Submitted by Preeti Jain, on March 19, 2020

Vector Class retainAll() method

  • retainAll() method is available in java.util package.
  • retainAll() method is used to retain all those elements of this Vector that exists in the given Collection.
  • retainAll() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
  • retainAll() method may throw an exception at the time of retaining element.
    NullPointerException: This exception may throw when the given parameter is null exists.


    public boolean retainAll(Collection co);


  • Collection co – represents the collection object that is to be retained in this Vector.

Return value:

The return type of the method is boolean, it returns true when element exists in the given collection is to be retained in this vector otherwise it returns false.


// Java program to demonstrate the example 
// of boolean retainAll(Collection co) method 
// of Vector 

import java.util.*;

public class RetainAllOfVector {
 public static void main(String[] args) {
  // Instantiates a Vector object  with
  // initial capacity of "10"
  Vector < String > v = new Vector < String > (10);
  ArrayList arr_l = new ArrayList();

  // By using add() method is to add the
  // elements in this v

  // By using add() method is to add the
  // elements in this arr_l

  // Display Vector and ArrayList
  System.out.println("v: " + v);
  System.out.println("arr_l: " + arr_l);

  // By using retainAll(arr_l) method is to
  // retain all elements of this vector v that
  // exists in the given collection arr_l

  // Display updated Vector
  System.out.println("v.retainAll(arr_l): " + v);


v: [C, C++, JAVA]
arr_l: [C, C++, SFDC]
v.retainAll(arr_l): [C, C++]

Comments and Discussions

Ad: Are you a blogger? Join our Blogging forum.

Languages: » C » C++ » C++ STL » Java » Data Structure » C#.Net » Android » Kotlin » SQL
Web Technologies: » PHP » Python » JavaScript » CSS » Ajax » Node.js » Web programming/HTML
Solved programs: » C » C++ » DS » Java » C#
Aptitude que. & ans.: » C » C++ » Java » DBMS
Interview que. & ans.: » C » Embedded C » Java » SEO » HR
CS Subjects: » CS Basics » O.S. » Networks » DBMS » Embedded Systems » Cloud Computing
» Machine learning » CS Organizations » Linux » DOS
More: » Articles » Puzzles » News/Updates

© https://www.includehelp.com some rights reserved.