CopyOnWriteArrayList removeAll() method in Java with Examples

The removeAll() method in CopyOnWriteArrayList class that removes all the elements that are contained in the specified collection from the CopyOnArrayList object you call on.

Syntax:

public boolean removeAll(Collection collection)

Parameter: The method accepts only a single parameter collection which is to be removed from the calling object.



Return Value: This method returns a boolean value. It returns true if this remove operation is successful.

Exception: This method throws following exceptions:

  • ClassCastException: if the class of an element of this list is incompatible with the specified collection.
  • NullPointerException: if the specified collection is null or if this list contains a null element and the specified collection does not permit null elements.

Below examples illustrates the removeAll() method:

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java program to demonstrate removeAll() method
  
import java.util.ArrayList;
import java.util.concurrent.CopyOnWriteArrayList;
  
public class Demo {
  
    public static void main(String args[])
    {
  
        // Get the CopyOnWriteArrayList
        CopyOnWriteArrayList<String> wishlist
            = new CopyOnWriteArrayList<>();
  
        // Add the elements in the CopyOnWriteArrayList
        wishlist.add("TV");
        wishlist.add("computer");
        wishlist.add("play station");
        wishlist.add("mobile");
        wishlist.add("smart watch");
  
        // Print the CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: \n"
                           + wishlist);
  
        // Get the collection to be removed
        ArrayList<String> checkList
            = new ArrayList<>();
  
        checkList.add("play station");
        checkList.add("TV");
        checkList.add("mobile");
  
        System.out.println("\nCollection to be removed:\n"
                           + checkList);
  
        // Remove the collection from CopyOnWriteArrayList
        // using removeAll() method
        wishlist.removeAll(checkList);
  
        // Print the CopyOnWriteArrayList after removal
        System.out.println("\nAfter removal of collection"
                           + " from CopyOnWriteArrayList:\n"
                           + wishlist);
    }
}

chevron_right






                        filter_none









Output:


CopyOnWriteArrayList: 
[TV, computer, play station, mobile, smart watch]

Collection to be removed:
[play station, TV, mobile]

After removal of collection from CopyOnWriteArrayList:
[computer, smart watch]





Example 2: To show NullPointerException











                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















// Java program to demonstrate removeAll() method 


  


import java.util.ArrayList; 


import java.util.concurrent.CopyOnWriteArrayList; 


  


public class Demo { 


  


    public static void main(String args[]) 


    { 


  


        // Get the CopyOnWriteArrayList 


        CopyOnWriteArrayList<String> wishlist 


            = new CopyOnWriteArrayList<>(); 


  


        // Add the elements in the CopyOnWriteArrayList 


        wishlist.add("TV"); 


        wishlist.add("computer"); 


        wishlist.add("play station"); 


        wishlist.add("mobile"); 


        wishlist.add("smart watch"); 


  


        // Print the CopyOnWriteArrayList 


        System.out.println("CopyOnWriteArrayList: \n"


                           + wishlist); 


  


        // Get the collection to be removed 


        ArrayList<String> checkList 


            = null; 


        System.out.println("\nCollection to be removed: "


                           + checkList); 


  


        try { 


  


            // Remove the collection from CopyOnWriteArrayList 


            // using removeAll() method 


            wishlist.removeAll(checkList); 


        } 


        catch (Exception e) { 


  


            // Print the Exception 


            System.out.println("\nException thrown"


                               + " while removing null "


                               + "from the CopyOnWriteArrayList: \n"


                               + e); 


        } 


    } 


} 



















                        chevron_right







                        filter_none









Output:


CopyOnWriteArrayList: 
[TV, computer, play station, mobile, smart watch]

Collection to be removed: null

Exception thrown while removing null from the CopyOnWriteArrayList: 
java.lang.NullPointerException





java-img





    

        My Personal Notes
        arrow_drop_up
    

    

        
        

            
            
        

    


Recommended Posts:
SandySharma
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.