File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
http://aspose.com/file-tools
The moose likes EJB and other Java EE Technologies and the fly likes General Queries for a J2EE Web Application Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


Win a copy of OCM Java EE 6 Enterprise Architect Exam Guide this week in the OCMJEA forum!
JavaRanch » Java Forums » Java » EJB and other Java EE Technologies
Bookmark "General Queries for a J2EE Web Application" Watch "General Queries for a J2EE Web Application" New topic
Author

General Queries for a J2EE Web Application

Vaibhav G Garg
Ranch Hand

Joined: Sep 23, 2011
Posts: 140
I have the following queries for a J2EE application. Appreciate your inputs on these.

1. What is the difference between Layer and Tier?

2. If we deploy the whole application like JSP, HTML, Servlets, Business Logic (POJOs), DAOs etc in one jar file, can we say that it uses multi-tier architecture or it is just one tier?

3. Does the definition of tier bound to the number of different servers the components deployed to? For Example, Servlets/JSP deployed to web server - Presentation Tier, Business Logic on App Server - Business Tier, Legacy DB - Data Tier? Or it is irrespective of the number of servers the application is deployed to?
Meiyappan Kannappa
Greenhorn

Joined: Sep 15, 2008
Posts: 10
Hi,

1. Difference between Tier and Layer:
Tier is physical separation, Seperate server machine for Application server, Database and web. Each physical machine is Tier. On other hand the term layer will be used to represent level of separation of your class structures. Your DAO will be a layer, BO will be layer, Action classes will be layer.

2. No, Please refer my answer to previous question.

3. Yes


Warm Regards
 
jQuery in Action, 2nd edition
 
subject: General Queries for a J2EE Web Application