Learn Basics of a Web server and Application Server

Application server and web servers are two types of servers crucial to understanding in web application development within the software world. The developer writes the code, packages it as a WAR file, and then deploys or hosts the code on these servers.

By utilizing either a web server or an application server, users can access the application’s features from anywhere in the world.

Web server basics:-

Web servers are utilized to generate both dynamic and static content. Clients send HTTP requests, which are then processed by the server, returning a response to the user. Web servers handle HTML content, images, and stylesheet elements. Popular web servers include Apache Web Server and Microsoft IIS.

A web server comprises both hardware and software, functioning as a machine with an IP address assigned to a domain name. For instance, when a client browser requests ”www.domainname.com/index.html🔗,” the web server on that machine retrieves the content of index.html and sends it back as a response to the browser. This communication occurs over the HTTP protocol defined by the W3C organization.

The web server is a fundamental component in web-based application development. Applications can be packaged as folders or web archives developed using Java, PHP, or Microsoft .NET technologies. The web server is commonly used for small-scale projects.

Application Servers tutorial:-

Application Servers are Java servers that offer a variety of reusable services.

Application servers are used in N-tier-based projects, where web servers act as front controllers for application servers.

It host EJB projects in the form of EAR (Enterprise Archive) structure, which contains JARs and WAR modules.

  • Object Lifecycle Management: This fundamental service within any application server involves creating a pool of objects, handling garbage collection, and managing the shared state of these objects among user session calls.

  • Connection Pooling: Application servers provide pre-created pools of connections to different databases, managing these connections and returning them to the pool when not in use by applications.

Security Management: Application servers offer various levels of security, including authorization and authentication, utilizing different providers such as database realms, text files, and various LDAP providers. Security is implemented at the domain object level, web resource level, and web context level.

Java Messaging Services (JMS): Application servers include built-in Java messaging services and are integrated with different JMS providers like SUN MQ providers.

Transaction Management: Application servers integrate with JTA (Java Transaction API) and ORM (Object-Relational Mapping) transactions to maintain ACID properties for application transactions.

Load Balancing and Clusters: To handle server loads, groups of application servers act as nodes connected within a cluster. They collectively serve responses, ensuring continued operation even if one node within the cluster fails.

Fault Tolerance: Application servers provide 99.999% uptime to ensure reliable applications with continuous 24/7 operation.

These are just a few of the services provided by application servers. Developers do not need to write these services when developing J2EE applications. Instead, they can focus on writing their business functionality code and reuse the services provided by the application server.

Difference Between Application Server and Web Server

Difference between the Application server and web servers is a basic interview question on j2ee world.

Application servers are utilized to furnish various business services, whereas web servers receive requests, fetch dynamic content, and relay responses to clients.

The architecture of application servers typically adheres to an N-tier node architecture, wherein numerous nodes are interconnected within a clustered environment.

Web servers, on the other hand, can operate within both 2-tier and N-tier architectures, serving as a front controller in the latter.

Here’s a list of popular application servers in the Java ecosystem:

The following are the list of popular application servers in java

  • apache Tomcat
  • Cache resin
  • BEA Weblogic later acquired by Oracle
  • Linux Jboss
  • IBM Websphere
  • SAP Netweaver WebAs 6.4
  • Oracle Application Server
  • Apache Geronima application server

And here are some widely-used web servers for web application development:

  • Apache webserver
  • Nginx
  • Microsoft IIS