Java ConcurrentLinkedQueue removeIf() Method
The removeIf() method of ConcurrentLinkedQueue class removes the elements of this queue that satisfies the given predicate filter.
Syntax:
public boolean removeIf(Predicate<? Super E> filter)
Parameters:
The parameter filter is a predicate which returns true for the elements to be removed.
Specified By:
The removeIf() method of ConcurrentLinkedQueue class is specified by:
removeIf in interface Collection<E>.
Return Value:
The removeIf () method returns a Boolean value 'true' if the collection has removed any element, else it returns 'false'.
Throws:
It throws NullPointerException if the specified filter is null.
Example 1
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.function.Predicate;
public class ConcurrentLinkedQueueRemoveIfExample1 {
public static void main(String[] args) {
ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();
for (int i=1;i<21;i++){
queue.add(i);}
System.out.println("Total no : "+ queue);
//removes all the elements which satisfies the predicate filter
Predicate<Integer> pr= a->(a>10);
queue.removeIf(pr );
System.out.println(" Number less than 11 = "+queue);
Test it Now
Output:
Total no : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
Number less than 11 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Example 2
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.function.Predicate;
public class ConcurrentLinkedQueueRemoveIfExample2 {
public static void main(String[] args) {
ConcurrentLinkedQueue<IsVoter> queue = new ConcurrentLinkedQueue<IsVoter>();
IsVoter isVoter1 = new IsVoter("Reema",18);
IsVoter isVoter2 = new IsVoter("Raj",7);
IsVoter isVoter3 = new IsVoter("Kajol",37);
IsVoter isVoter4 = new IsVoter("Ravi",47);
IsVoter isVoter5 = new IsVoter("Varun",17);
queue.add(isVoter1);
queue.add(isVoter2);
queue.add(isVoter3);
queue.add(isVoter4);
queue.add(isVoter5);
//removes all the elements which satisfies the Predicate filter
Predicate<IsVoter> pr= (IsVoter age) ->(age.age < 18);
queue.removeIf(pr );
System.out.println(" People eligible to vote : ");
for (IsVoter xyz : queue ){
System.out.println(xyz);
class IsVoter {
String name;
int age;
public IsVoter(String name, int age) {
this.name = name;
this.age = age;
public String toString() {
return "Name = " + this.name + " Age = " + this.age;
Test it Now
Output:
People eligible to vote :
Name = Reema Age = 18
Name = Kajol Age = 37
Name = Ravi Age = 47
Example 3
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.function.Predicate;
public class ConcurrentLinkedQueueRemoveIfExample3 {
public static void main(String[] args) {
ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();
for (int i=1;i<21;i++){
queue.add(i);}
System.out.println("Total no : "+ queue);
//removes all the elements which satisfies the predicate filter
Predicate<Integer> pr=null;
queue.removeIf(pr );
System.out.println(queue);
Test it Now
Output:
Exception in thread "main" java.lang.NullPointerException
at java.util.Objects.requireNonNull(Objects.java:203)
Total no : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
at java.util.Collection.removeIf(Collection.java:410)
at com.javaTpoint.ConcurrentLinkedQueueRemoveIfExample3.main(ConcurrentLinkedQueueRemoveIfExample3.java:13)
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