ArrayList removeAll() method in Java with Examples

The removeAll() method of java.util.ArrayList class is used to remove from this list all of its elements that are contained in the specified collection.

Syntax:

public boolean removeAll(Collection c)

Parameters: This method takes collection c as a parameter containing elements to be removed from this list.

Returns Value: This method returns true if this list changed as a result of the call.

Exception: This method throws NullPointerException if this list contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null.



Below are the examples to illustrate the removeAll() method.

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java program to demonstrate
// removeAll() method for Integer value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
  
        try {
  
            // Creating object of ArrayList<Integer>
            ArrayList<Integer>
                arrlist1 = new ArrayList<Integer>();
  
            // Populating arrlist1
            arrlist1.add(1);
            arrlist1.add(2);
            arrlist1.add(3);
            arrlist1.add(4);
            arrlist1.add(5);
  
            // print arrlist1
            System.out.println("ArrayList before "
                               + "removeAll() operation : "
                               + arrlist1);
  
            // Creating another object of  ArrayList<Integer>
            ArrayList<Integer>
                arrlist2 = new ArrayList<Integer>();
            arrlist2.add(1);
            arrlist2.add(2);
            arrlist2.add(3);
  
            // print arrlist2
            System.out.println("Collection Elements"
                               + " to be removed : "
                               + arrlist2);
  
            // Removing elements from arrlist
            // specified in arrlist2
            // using removeAll() method
            arrlist1.removeAll(arrlist2);
  
            // print arrlist1
            System.out.println("ArrayList after "
                               + "removeAll() operation : "
                               + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

chevron_right


Output:

ArrayList before removeAll() operation : [1, 2, 3, 4, 5]
Collection Elements to be removed : [1, 2, 3]
ArrayList after removeAll() operation : [4, 5]

Example 2: For NullPointerException

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java program to demonstrate
// removeAll() method for Integer value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
  
        try {
  
            // Creating object of ArrayList<Integer>
            ArrayList<Integer>
                arrlist1 = new ArrayList<Integer>();
  
            // Populating arrlist1
            arrlist1.add(1);
            arrlist1.add(2);
            arrlist1.add(3);
            arrlist1.add(4);
            arrlist1.add(5);
  
            // print arrlist1
            System.out.println("ArrayList before "
                               + "removeAll() operation : "
                               + arrlist1);
  
            // Creating another object of  ArrayList<Integer>
            ArrayList<Integer>
                arrlist2 = null;
  
            // print arrlist2
            System.out.println("Collection Elements"
                               + " to be removed : "
                               + arrlist2);
  
            System.out.println("\nTrying to pass "
                               + "null as a specified elelemnt\n");
  
            // Removing elements from arrlist
            // specified in arrlist2
            // using removeAll() method
            arrlist1.removeAll(arrlist2);
  
            // print arrlist1
            System.out.println("ArrayList after "
                               + "removeAll() operation : "
                               + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

chevron_right


Output:

ArrayList before removeAll() operation : [1, 2, 3, 4, 5]
Collection Elements to be removed : null

Trying to pass null as a specified elelemnt

Exception thrown : java.lang.NullPointerException


My Personal Notes arrow_drop_up

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.



Improved By : Akanksha_Rai