What are the Components of a Java application?
Lets see what are the components of a java application. Java web application consists of several different components, each serving a different purpose.
MVC, stands for Model View Controller . It is the most popular Architectural design pattern.
Lets see various components of a J2EE application.
- Client/Browser - it needs a web address with a URL.
- JSP (Java Server Pages) – JSP is a server side technology intended to present data to the user. It supports display of dynamic content with the help of special tags called JSP tags,which help insert Java code with in HTML pages. [Static HTML always displays the same content]. At runtime, a JSP is converted to a Servlet. Business logic is not typically written here.
- JSF (Java Server Faces) – JSF is a view component framework for effective design of the User Interface.
- Servlet – A Servlet validates the data received from the input, selects the appropriate business logic code, and passes on the values to the Bean code.
- Enterprise Java Bean (EJB) – This is where the entire business logic is typically written and handled. The bean then calls the code to either read, write or update the database. Once the database operations are complete, the response is then transferred back to the Servlet, which in turn selects the appropriate JSP to display the results.
- WebServices – Webservices are components of an application which run on a separate server and communicate over HTTP protocol.
- Database – stores the entire data of the application.
Here is a special note : not all web applications follow the JSP -> Servlet -> EJB -> Database model.
Most of the J2EE applications are currently written with a framework such as Struts, Spring, or Hibernate. The design of applications vary for each requirement based on size of the application, cost, development time, resources and team size.
We will see what are the various types of testing that need to be carried out to ensure a high quality, bug free application, in the next post .