There has being varying opinions about the difference between app server and web server . But I have taken to come with a vivid research on the difference between webserver and application server.
Difference Between App Server And Web Server
A Web server handle and serve the HTTP protocol or content. It also provides RMI/RPC which is another form of protocol support.
Meanwhile, web Server is mainly designed to serve static content, however most of them have plugins to support scripting languages such as Perl, PHP, ASP, JSP and the likes through which these servers generates a dynamic HTTP content.
On the reception of HTTP request on the web server, it responds with a HTTP, that is like sending back an HTML page.
It can also be directed to some other server-side technology. In consequence, notwithstanding their purpose, response generated by server-side programs are usually in HTML, for viewing in a Web browser.
On the other hand, Application server deals with several different protocols, including, but not limited, to HTTP. While a web server is delegated mainly HTTP protocols, the application.
The Web server is saddled with the responsibility of displaying the site’s content and the application server is responsible for the logic and as well the interaction between the user and the displayed content.
Similarities Between App Server And Web Server Compared side-by-side
The application server is works in conjunction with the web server, while one displays and the other is concerned with interaction. A very large number of application servers have Web Server as an integral part of them. This simply means that an App Server can do whatever Web Server is capable of.
In addition App Server have components with features to enable application level services like Connection Pooling, Object Pooling, Transaction Support, Messaging services and lots more.
Moreover, as web servers are well suited for static content and app servers for dynamic content, most of the production environments have web server acting as reverse proxy to app server.
That means while responding to a page request, static contents like images or Static HTML are served by web server which interprets the request.
Moreover, using some of filtering technique (mostly extension of the requested resource) web server identifies dynamic content request and transparently forwards to app server.
An instance of such configuration is Apache Tomcat HTTP Server and Oracle WebLogic Server. Apache Tomcat HTTP Server is Web Server and Oracle WebLogic is Application Server.
In some cases the servers are tightly integrated such as IIS and .NET Runtime. IIS is web server. When equipped with .NET runtime environment, IIS is capable of providing application services.
While a Web server may not itself support transactions or database connection pooling, it may employ various strategies for fault tolerance and scalability such as load balancing, caching, and clustering. However, features often times erroneously assigned as features reserved only for application servers.
An application server exposes business logic to client applications through various protocols, possibly including HTTP. An application server provides access to business logic for use by client application programs.
The application program can use this logic just as it would call a method on an object. Such application server clients can include GUIs (graphical user interface) running on a PC, a Web server, or even other application servers.
The information traveling back and forth between an application server and its client is not restricted to simple display markup.
Instead, the information is program logic. Since the logic takes the form of data and method calls and not static HTML, the client can employ the exposed business logic however it wants.
In most cases, the server exposes this business logic through a component API, such as the EJB (Enterprise JavaBean) component model found on J2EE (Java 2 Platform, Enterprise Edition) application servers. Moreover, the application server manages its own resources.
Such gate-keeping duties include security, transaction processing, resource pooling, and messaging. Like a Web server, an application server may also employ various scalability and fault-tolerance techniques.
SOME NOTABLE DIFFERENCES BETWEEN WEBSERVER AND APPLICATION SERVER
Application server is used to serve web based applications and enterprise based applications(i.e servlets, jsps and ejbs…). Application servers may contain a web server internally. Web server is used to serve web based applications.(i.e servlets and jsps).
To deliver various applications to another device, it allows everyone in the network to run software off of the same machine. Keeping HTML, PHP, ASP, etc files available for the web browsers to view when a user accesses the site on the web, handles HTTP requests from clients.
Web server manage and execute web applications(war) where as in Application server it manage and execute web applications (war),Ejb components (jar) and enterprise Applications (Ear).
Web Server uses only Servlet Container, Jsp container where as in application Server uses Servlet Container ,Jsp container ,Ejb Container.
Web server Developed based on servlet ,Jsp technologies of JEE module where as Application Server devloped based on Servlet, Jsp,Ejb,Jms,Jta,Java mail of JEE.
In conclusion, web server supports only http,https protocol Application server supports http,https,iiop,rmi protocols. Web server Suitable for Small scale and medium scale web applications. Application server Generally used for large scale. Hence the glaring Difference Between App Server And Web Server.