Java ConcurrentLinkedQueue retainAll() Method

by Online Tutorials Library July 22, 2022

Java ConcurrentLinkedQueue retainAll() method

The retainAll() method of ConcurrentLinkedQueue class keeps only those elements in this queue that are present in the defined collection.

Syntax:

Specified By:

The retainAll() method of ConcurrentLinkedQueue class is specified by :

retainAll() method in interface Collection<E>.

Override:

The retainAll() method of ConcurrentLinkedQueue class is overrided by:

retainAll() method in class AbstractCollection<E>.

Parameters:

c – The collection contains the elements which is to be kept in this collection.

Return Value:

The retainAll() method returns true if this collection changes as a result of the call.

Throws:

The retainAll() method throws NullPointerException if this collection contains one or more null elements.

Example 1

  import java.util.ArrayList;  import java.util.List;  import java.util.concurrent.ConcurrentLinkedQueue;  public class ConcurrentLinkedQueueRetainAllExample1 {      public static void main(String[] args) throws InterruptedException {          List<Integer> list = new ArrayList<Integer>();          ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();          for (int i=1;i<21;i++){              queue.add(i);          }          System.out.println(” Elements in queue : ” + queue);          for (int i = 1; i < 11; i++) {              int j = i *5;              list.add(j);          }          //will give the elements int the queue which are present in list          queue.retainAll(list);          System.out.println(” Multiple of 5 : ” + queue);      }  }  

Test it Now

Output:

Elements in queue : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]   Multiple of 5 : [5, 10, 15, 20]

Example 2

  import java.util.ArrayList;  import java.util.List;  import java.util.concurrent.ConcurrentLinkedQueue;  public class ConcurrentLinkedQueueRetainAllExample2 {      static int i=1;      public static void main(String[] args) {          List<String> list = new ArrayList<String>();          ConcurrentLinkedQueue<String> queue = new ConcurrentLinkedQueue<String>();          queue.add(“Reema”);          queue.add(“Ranjeeta”);          queue.add(“Rani”);          queue.add(“Sukla”);          queue.add(“Raj”);          System.out.println(“Students in the class : “);          for (String str : queue){              System.out.println(i++ +”.”+str);          }          list.add(“Raj”);          list.add(“Rani”);          list.add(“Ranjeeta”);          queue.retainAll(list);          System.out.println(“Students failed : “);          i=1;          for (String str : queue){              System.out.println(i++ +”.”+str);          }      }  }  

Test it Now

Output:

1.Reema  2.Ranjeeta  3.Rani  4.Sukla  5.Raj  Students failed :   1.Ranjeeta  2.Rani  3.Raj

Example 3

  import java.util.TreeSet;  import java.util.concurrent.ConcurrentLinkedQueue;  public class ConcurrentLinkedQueueRetainAllExample3 {      public static void main(String[] args) {          TreeSet<Integer> list = new TreeSet<Integer>();          ConcurrentLinkedQueue<Integer> queue = new ConcurrentLinkedQueue<Integer>();          for (int i=1;i<21;i++){              queue.add(i);          }          list.add(101);          list.add(null);          queue.retainAll(list);          System.out.println(“Queue = “+queue);      }  }  

Test it Now

Output:

Exception in thread "main" java.lang.NullPointerException  at java.util.TreeMap.put(TreeMap.java:563)  at java.util.TreeSet.add(TreeSet.java:255)  at com.tutorAspire.ConcurrentLinkedQueueRetainAllExample3.main(ConcurrentLinkedQueueRetainAllExample3.java:13)

Next TopicJava ConcurrentLinkedQueue

Java ConcurrentLinkedQueue retainAll() Method

Java ConcurrentLinkedQueue retainAll() method

Syntax:

Specified By:

Override:

Parameters:

Return Value:

Throws:

Example 1

Example 2

Example 3

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