Only one instance of the System.Web.Hosting.ApplicationManager object is created by an ASP.NET host process in the default application domain. If an instance of the System.Web.Hosting.ApplicationManager class is not available, the ApplicationManager.GetApplicationManager method first creates an instance of the System.Web.Hosting.ApplicationManager class and then returns the newly created object. If an instance of the System.Web.Hosting.ApplicationManager class was previously created, the ApplicationManager.GetApplicationManager method returns the existing object.