The removeAll() method of CopyonWriteArraySet method removes all the elements of this CopyOnWriteArraySet that are present in the specified collection. That means elements which are common in both the collections are removed from this CopyOnWriteArraySet.
Syntax:
public boolean removeAll(Collection<E> c)
Parameters: This method accepts a parameter c which is the collection containing elements to be removed from this set.
Return Value: This method returns a boolean value such as true, if the CopyOnWriteArraySet is changed. Else this method returns false.
Exceptions: This method throws following Exceptions:
- ClassCastException: if the class of an element of this set is incompatible with the specified collection
- NullPointerException: if this set contains a null element and the specified collection does not permit null elements, or if the specified collection is null.
Below program illustrates the removeAll() function of CopyOnWriteArrayList class:
Program 1:
// Java Program to illustrate the CopyOnWriteArraySet// removeall() method in Java import java.util.concurrent.CopyOnWriteArraySet;import java.util.*; public class GFG { public static void main(String[] args) { // create object of CopyOnWriteArraySet CopyOnWriteArraySet<Integer> ArrSet = new CopyOnWriteArraySet<Integer>(); // Add elements ArrSet.add(10); ArrSet.add(20); ArrSet.add(30); ArrSet.add(50); // print CopyOnWriteArraySet System.out.println("CopyOnWriteArraySet: " + ArrSet); // create object of ArrayList ArrayList<Integer> Arrlist = new ArrayList<Integer>(); // add elements Arrlist.add(10); Arrlist.add(30); Arrlist.add(40); // print ArrayList System.out.println("ArrayList: " + Arrlist); // removing the common elements from // the CopyOnWriteArraySet using removeAll() System.out.println("Elements removed " + "from CopyOnWriteArraySet: " + ArrSet.removeAll(Arrlist)); // print updated CopyOnWriteArraySet System.out.println("Updated CopyOnWriteArraySet: " + ArrSet); }} |
Output:
CopyOnWriteArraySet: [10, 20, 30, 50] ArrayList: [10, 30, 40] Elements removed from CopyOnWriteArraySet: true Updated CopyOnWriteArraySet: [20, 50]
Program 2: To show NullpointerException
// Java Program to illustrate the CopyOnWriteArraySet// removeall() method in Java import java.util.concurrent.CopyOnWriteArraySet;import java.util.*; public class GFG { public static void main(String[] args) { // create object of CopyOnWriteArraySet CopyOnWriteArraySet<Integer> ArrSet = new CopyOnWriteArraySet<Integer>(); // Add elements ArrSet.add(10); ArrSet.add(20); ArrSet.add(30); ArrSet.add(50); // print CopyOnWriteArraySet System.out.println("CopyOnWriteArraySet: " + ArrSet); try { // removing the null from // the CopyOnWriteArraySet using removeAll() // This will throw NullPointerException System.out.println("Elements removed " + "from CopyOnWriteArraySet: " + ArrSet.removeAll(null)); } catch (Exception e) { System.out.println(e); } }} |
Output:
CopyOnWriteArraySet: [10, 20, 30, 50] java.lang.NullPointerException