Queue.Synchronized() Method in C#

Last Updated : 11 Jul, 2025

This method is used to return a new Queue that wraps the original queue and is thread-safe. The wrapper returned by this method locks the queue before an operation is performed so that it is performed in a thread-safe manner. Syntax:

public static System.Collections.Queue Synchronized (System.Collections.Queue queue);

Return Value: A Queue wrapper that is synchronized (thread safe). Exception: This method will give ArgumentNullException if the queue is null. Below programs illustrate the use of above-discussed method: Example 1:

csharp

// C# code to illustrate the // Queue.Synchronized() Method using System; using System.Collections; class GFG {  // Driver code  public static void Main()  {  // Creating a Queue  Queue myQueue = new Queue();  // Inserting the elements into the Queue  myQueue.Enqueue("C");  myQueue.Enqueue("C++");  myQueue.Enqueue("Java");  myQueue.Enqueue("C#");  myQueue.Enqueue("HTML");  myQueue.Enqueue("CSS");  // Creates a synchronized  // wrapper around the Queue  Queue sq = Queue.Synchronized(myQueue);  // Displays the synchronization  // status of both ArrayList  Console.WriteLine("myQueue is {0}.", myQueue.IsSynchronized ?  "Synchronized" : "Not Synchronized");  Console.WriteLine("sq is {0}.", sq.IsSynchronized ?   "Synchronized" : "Not Synchronized");  } }

Output:

 myQueue is Not Synchronized. sq is Synchronized.

Example 2:

csharp

// C# code to illustrate the // Queue.Synchronized() Method using System; using System.Collections; class GFG {  // Driver code  public static void Main()  {  // Creating a Queue  Queue myQueue = new Queue();  // Inserting the elements into the Queue  myQueue.Enqueue("Geeks");  myQueue.Enqueue("for");  myQueue.Enqueue("Geeks");  myQueue.Enqueue("Noida");  myQueue.Enqueue("Sector");  myQueue.Enqueue("142");  // it will give error as  // the parameter is null  Queue smyList = Queue.Synchronized(null);  } }