AbstractCollection removeAll() method in Java with Example
The Java.util.AbstractCollection.removeAll(Collection col) method is used to remove all the elements from the AbstractCollection, present in the collection specified.
Syntax:
AbstractCollection.removeAll(Collection col)
Parameters: This method accepts a mandatory parameter col which is the collection whose elements are to be removed from the AbstractCollection.
Return Value: This method returns true if the AbstractCollection is altered due to the operation at all, else False.
Exception: The method throws NullPointerException if the specified collection is null.
Below programs illustrate the Java.util.AbstractCollection.removeAll(Collection col) method:
Program 1:
// Java code to illustrate removeAll()import java.util.*; public class AbstractCollectionDemo { public static void main(String args[]) { // Creating an empty AbstractCollection AbstractCollection<String> collection = new ArrayList<String>(); // Use add() method to add // elements in the AbstractCollection collection.add("Geeks"); collection.add("for"); collection.add("Geeks"); collection.add("10"); collection.add("20"); // Output the AbstractCollection System.out.println("AbstractCollection: " + collection); // Creating an empty AbstractCollection AbstractCollection<String> colcollection = new ArrayList<String>(); // Use add() method to add // elements in the AbstractCollection colcollection.add("Geeks"); colcollection.add("for"); colcollection.add("Geeks"); // Remove the head using remove() boolean changed = collection.removeAll(colcollection); // Print the result if (changed) System.out.println("Collection removed"); else System.out.println("Collection not removed"); // Print the final AbstractCollection System.out.println("Final AbstractCollection: " + collection); }} |
Output:
AbstractCollection: [Geeks, for, Geeks, 10, 20] Collection removed Final AbstractCollection: [10, 20]
Program 2:
// Java code to illustrate removeAll()import java.util.*; public class AbstractCollectionDemo { public static void main(String args[]) { // Creating an empty AbstractCollection AbstractCollection<Integer> collection = new ArrayList<Integer>(); // Use add() method to // add elements in the AbstractCollection collection.add(1); collection.add(2); collection.add(3); collection.add(10); collection.add(20); // Output the AbstractCollection System.out.println("AbstractCollection: " + collection); // Creating an empty AbstractCollection AbstractCollection<Integer> colcollection = new ArrayList<Integer>(); // Use add() method to add elements // in the AbstractCollection colcollection.add(30); colcollection.add(40); colcollection.add(50); // Remove the head using remove() boolean changed = collection.removeAll(colcollection); // Print the result if (changed) System.out.println("Collection removed"); else System.out.println("Collection not removed"); // Print the final AbstractCollection System.out.println("Final AbstractCollection: " + collection); }} |
Output:
AbstractCollection: [1, 2, 3, 10, 20] Collection not removed Final AbstractCollection: [1, 2, 3, 10, 20]
