Why do we need Application Server in Java

Question

Why do we need Application Server in Java like JBoss or WebSphere. Is it possible that we develop large scale website only with Java (Apache Tomcat). Where thousand of user connect on site at a moment. An example is a website like b2b.

What is the cost of a Application Server? I will be thankful if you compare price among different application server and if there is any free version kindly highlight it.

Answer 1

Application Servers are mostly used if you want to use advanced features like transaction management, hot code swapping and advanced persistence.

There are application servers that are open source. E.g. GlassFish and JBoss.

I don't think you need an application server for building a popular web site, you'll also be fine with a servlet container like Tomcat or Jetty.

Answer 2

In short Application Servers provide you with few services like

• Transaction Management
• Load Balancing
• Security
• Threading

etc.

You have to take care of these things yourself in a Web Server.

There are few Open Source Application servers which are free of cost.

I have used Glassfish.