Explain the following: a.) SPSite b.) SPWeb

Both are classes of SharePoint Server side object model. Under SharePoint web application, you can have multiple site collections and under a site collection you can have multiple sites/subsites. To access/update site collection properties, object of SPSite class is used. And to access/update root site of site collction or sub site properties, object of SPWeb class is used.

a.) SPSite - i.)It is a site collection and an be represented as SPSite class in the object model. ii.)SPSite object is a primary entry points to the server object model. iii.)It is used frequently in SharePoint application development. b.) SPWeb - i.) It is a specific site under site collection in Sharepoint. ii.) It is represented as SPWeb class in the server object model.