Java Collections checkedQueue() Method with Examples

by Online Tutorials Library July 22, 2022

Java Collections checkedQueue() Method

The checkedQueue() is a method of Java Collections class which returns a dynamically typesafe view of the specified Queue. If an element inserted of the wrong type, it will result in an immediate ClassCastException.

Syntax

Following is the declaration of checkedQueue() method:

Parameter

Parameter	Description	Required/Optional
queue	It is the Queue for which a dynamically typesafe view is to be returned.	Required
type	It is the type of element that Queue is permitted to hold.	Required

Returns

The checkedQueue() method returns a dynamically typesafe view of the specified Queue.

Exceptions

ClassCastException

Compatibility Version

Java 1.8 and above

Example 1

  import java.util.*;  public class CollectionsCheckedQueueExample1 {  public static void main(String[] args) {  //Create list               Queue queue = new PriorityQueue();        queue.add(“A”);        queue.add(“B”);        queue.add(“C”);        queue.add(“D”);        //Create type safe view of the List                  System.out.println(“Type safe view of the Queue is: “+Collections.checkedQueue(queue,String.class));        }  }  

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Output:

Type safe view of the Queue is: [A, B, C, D]

Example 2

  import java.util.*;  public class CollectionsCheckedQueueExample2 {  public static void main(String[] args) {   //Create list               Queue queue = new PriorityQueue();        queue.add(55);        queue.add(66);        queue.add(77);        queue.add(77);        queue.add(88);        queue.add(66);        //Create type safe view of the List                  System.out.println(“Type safe view of the Queue is: “+Collections.checkedQueue(queue,Integer.class));        }  }  

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Output:

Type safe view of the Queue is: [55, 66, 66, 77, 88, 77]

Example 3

  import java.util.*;  public class CollectionsCheckedQueueExample3 {  public static void main(String[] args) {  Queue queue = new PriorityQueue<>();              queue = Collections.checkedQueue(queue, Integer.class);              queue.offer(1);              queue.offer(2);              queue.offer(5);              System.out.println(“n”+queue);              Queue queue2 = queue;              queue2.offer(“Four”);              System.out.println(queue2);        }  }  

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Output:

[1, 2, 5]  Exception in thread "main" java.lang.ClassCastException: Attempt to insert class java.lang.String element into collection with element type class java.lang.Integer  at java.base/java.util.Collections$CheckedCollection.typeCheck(Collections.java:3038)  at java.base/java.util.Collections$CheckedQueue.offer(Collections.java:3188)  at myPackage.CollectionCheckedQueueExample3.main(CollectionCheckedQueueExample3.java:12)

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Java Collections checkedQueue() Method with Examples

Java Collections checkedQueue() Method

Syntax

Parameter

Returns

Exceptions

Compatibility Version

Example 1

Example 2

Example 3

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