Application Server

Application Servers are used to create and run web based applications. They contain a very comprehensive and structured service layer model. They are accessed by the users through an API. Apart from aiding the creation of web page, an application server also provides other services such as clustering, fail-over, and load-balancing, so developers can focus on implementing the business logic.  In a nutshell, an application server can be termed as an environment which lets any application to run.