Vector retainAll() method in Java with Examples

The retainAll method of class vector in java is an inbuilt function in Java which is used to retains only the elements in this Vector that are contained in the specified Collection. In other words, removes from this Vector all of its elements that are not contained in the specified Collection.

Syntax:

public boolean retainAll(Collection c)

Parameter: Here c is a collection of elements to be retained in this Vector (all other elements are removed).

Return value: This method will return a boolean value, i.e true if this Vector changed as a result of the call or else false.

Exception: This method will throw the following exceptions.



  • ClassCastException – If the types of one or more elements in this vector are incompatible with the specified collection.
  • NullPointerException –If this vector contains one or more null elements and the specified collection does not support null elements, or if the specified collection is null.

    • Below programs illustrate the Vector.retainAll() method in Java:

    Program 1:To illustrate Vector.retainAll() method in Java.

    filter_none

    edit
    close

    play_arrow

    link
    brightness_4
    code

    import java.util.*;
    import java.io.*;
    public class GFG {
        public static void main(String args[])
        {
            // Creating an empty Vector
            Vector<String> v1 = new Vector<String>();
      
            // adding elements to the vector v1
            v1.add("Geeks");
            v1.add("For");
            v1.add("Geeks");
            v1.add("is");
            v1.add("a");
            v1.add("computer");
            v1.add("science");
            v1.add("portal");
      
            System.out.println("Elements of vector1:" + v1);
      
            // Creating an other empty vector
            Vector<String> v2 = new Vector<String>();
      
            // adding elements to the vector v2
            v2.add("Geeks");
            v2.add("For");
            v2.add("Geeks");
            v2.add("contains");
            v2.add("well");
            v2.add("written");
            v2.add("programming");
            v2.add("articles");
            v2.add("and");
            v2.add("much");
            v2.add("more.");
      
            System.out.println("Elements of vector2:" + v2);
      
            System.out.println("Calling retainAll() method");
            // calling retainAll()
            v1.retainAll(v2);
      
            System.out.println("After calling retainAll() method");
            System.out.println(v1);
        }
    }

    chevron_right

    

    

    
                        filter_none
    

    

    

    

    
Output:
    

    
Elements of vector1:[Geeks, For, Geeks, is, a, computer, science, portal]
    
Elements of vector2:[Geeks, For, Geeks, contains, well, written, programming, articles, and, much, more.]
    
Calling retainAll() method
    
After calling retainAll() method
    
[Geeks, For, Geeks]

    

    

    Program 2:To show return value of retainAll() method in Java.
    

    

    

    

    

    
                                    filter_none
    

    

                                        edit
    
                                    close
    

    

                                        play_arrow
    

    

                                        link
    
                                    brightness_4
    
                                    code
                                
    

    

    

    

    

    

    


    


    

    import java.util.*; 
    

    import java.io.*; 
    

      
    

    public class GFG { 
    

        public static void main(String args[]) 
    

        { 
    

      
    

            // Creating an empty Vector 
    

            Vector<String> v1 = new Vector<String>(); 
    

      
    

            // adding elements to the vector v1 
    

            v1.add("Geeks"); 
    

            v1.add("For"); 
    

            v1.add("Geeks"); 
    

            v1.add("is"); 
    

            v1.add("a"); 
    

            v1.add("computer"); 
    

            v1.add("science"); 
    

            v1.add("portal"); 
    

      
    

            System.out.println("Elements of vector1:" + v1); 
    

      
    

            // Creating an other empty vector 
    

            Vector<String> v2 = new Vector<String>(); 
    

      
    

            // adding elements to the vector v2 
    

            v2.add("Geeks"); 
    

            v2.add("For"); 
    

            v2.add("Geeks"); 
    

            v2.add("contains"); 
    

            v2.add("well"); 
    

            v2.add("written"); 
    

            v2.add("programming"); 
    

            v2.add("articles"); 
    

            v2.add("and"); 
    

            v2.add("many"); 
    

            v2.add("more."); 
    

      
    

            System.out.println("Elements of vector1:" + v1); 
    

      
    

            // calling retainAll() 
    

            boolean t = v1.retainAll(v2); 
    

      
    

            System.out.println("Calling retainAll() method: "); 
    

            System.out.println(t); 
    

        } 
    

    } 
    

    
    		

    
    

    

    

    

    

    

    
                        chevron_right
    

    

    

    
                        filter_none
    

    

    

    

    
Output:
    

    
Elements of vector1:[Geeks, For, Geeks, is, a, computer, science, portal]
    
Elements of vector1:[Geeks, For, Geeks, is, a, computer, science, portal]
    
Calling retainAll() method:
    
true
    

    

    

    Attention reader! Don’t stop learning now. Get hold of all the important Java and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.
    



    
    
    
        My Personal Notes
        arrow_drop_up
    
    
    
    
        
        
    
            
            
        
    
    
    

    Recommended Posts:
    suman_ptnl
    Check out this Author's contributed articles.
    If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
    Please Improve this article if you find anything incorrect by clicking on  the "Improve Article" button below.