Application server Vs Web server

Question

I'm more or less familiar with APACHE and LAMP but I can't see what an application server is. Can someone please explain to me the difference between an application server and a web server?

Solution 1

You know web servers: they handle HTTP requests.

App servers are generally used in the Java EE space. They may or may not have a web server built in. They add servlet/JSP support (servlets are Java classes that run in an app server and listen for HTTP requests; JSPs are Java Server Pages, a templating solution that uses servlets to generate HTML) and sometimes EJBs (Enterprise Java Beans).

The app server provides services such as threading, naming, pooling, etc. to objects that run inside it.

Solution 2

An application server runs applications/services to be used by various clients. In general it allows you to deploy and manage applications which need to run on a server machine instead of on a desktop.

It offers typically a large set of services to be used by the applicaitons such as security, messaging, transaction coordination, etc...

It may or may not have a web server as part of the package (but most do).

A web server only deals with handling HTTP requests and returning web pages and other static or dynamic content.

In practice the line dividing web servers is not razor sharp and there is a sizable grey area between the two.

Solution 3

A Web server handles the HTTP protocol. When the Web server receives an HTTP request, it responds with an HTTP response, such as sending back an HTML page.

An application server exposes business logic to client applications through various protocols, possibly including HTTP. While a Web server mainly deals with sending HTML for display in a Web browser, an application server provides access to business logic for use by client application programs.

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Comments

[duffymo]

Why was this voted down?

[cbmeeks]

+1 from me. Nice, short, concise answer.