What is the difference between Cache object and Application object?

               The main difference between the Cache and Application objects is that the Cache object provides cache-specific features, such as dependencies and expiration policies

  How to get access to Cache object ?

              The Cache object is defined in the System.Web.Caching namespace. You can get a reference to the Cache object by using the Cache property of the HttpContext class in the System.Web namespace or by using the Cache property of the Page object