Struts

Web application as a program that resides on a Web server and produces dynamically or static created pages in a hypertext markup language (most commonly HTML) in response to a user’s request. A user make request by clicking the link or button on the web page. To built the Web application, Java 2 Enterprise Edition (J2EE) must be used.

Web Container :

A web container is a program that manages the components of a Web application, in particular JSP pages and Java Servlets. A Web container provides a number of services, such as

• Life-Cycle management : Web container provide the process of starting up and shutting down a component.
• Concurrency : Provide the capability to process more than one action at a time.
• Security : Provide the restricted access to components, such as username & password protection.
• Portability : Access anywhere, taking very less resource.

Apache Tomcat & GlassFish Server are the example of a Web container, — an open-source implementation of the J2EE Java Servlet and JavaServer Pages (JSP) specifications. A specification is a document that describes all the details of a technology. Typically, a Web container also functions as a Web server, providing basic HTTP (Hypertext Transfer Protocol) support for users who want to access information on the site.