AbstractCollection removeAll() method in Java with Example
Last Updated :
24 Dec, 2018
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
// 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
// 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]