(2) The classification of middleware can be divided into bottom-type middleware

(2) The classification of middleware can be divided into bottom-type middleware general-purpose middleware and integrated middleware from a hierarchical perspective.
The underlying middleware is represented by Sun's JVM and Microsoft's CLR; the general-purpose middleware is represented by BEA's Weblogic and IBM's MQSeries; the integrated middleware is represented by Weblogic and IBM's WebSphere. 3.3 Extensible Markup Language XML is a set of rules that define semantic markup that divides a document into many parts and identifies these parts.