JAVA TECHNOLOGIES By Ashok kumar , MCA 3rd semester 2018
UNIT - I Q. Explain J2EE Multitier Architecture OR Explain the functionality of J2EE Multitier Architecture .
Java is a Technology that provide developing and deploying J2EE application . J2EE consist , J2EE component , Application programming Interface (API), services and protocols to develop J2EE Application and web based Application. J2EE Multitier Architecture have four tiers :1. 2. 3. 4. Client Tier (Presentation / Application ) Web Tier EJB Tier EIS Tier 1. Client Tier :Client as a browser and user directly interact with application . It request to web tier (Servlet and JSP) and Response from web server . It‟s provide Accepting data to the lower layer and give to higher layer. - Client tier catagories of three No. of Ways : (i) Applet line :- It is an client of web Tier (ii) Application client :(iii) Rich line:- Which build in other than Java Note:- ACL ( Access control List ) :It means what can Access by whom. 2. Web Tier :It is a J2EE server container machine than consist servlet or JSP or other components . Servlet or JSP request to the EJB Tier (It is a J2ee EJB server machine ) through get or post method .
It response from Business logic or EJB Tier to Operation of Servlet and JSP . Servlet is a Java class file that run on server machine and generate output on client servlet have a HTML file to servlet mapping. JSP ( Java server pages) that have own tags in which use java core The purpose of web Tier is providing internet functionality to the Enterprise Application or J2EE to use HTTP to receive request from and send response to client that could resides on any Tier . web tier is like web server that have a Tomcat server. 3. EJB Tier : This tier provide business logic or meant what service or business rulear purpose of the application written in EJB code. All the components are know as software objects. It is represent a real world objects. EJB tier again response to the request coming from web tier. EJB Components are :(i) (ii) (iii) Session beans :- Maintain a session of state. Entity beans:- Create a entity. Message driven beans It‟s responsible for low level system services that are required to implement business logic of a enterprise java beans. Object server provide and object when required it. RMI :- Remote method innvocation. JRMP :- java remote method protocol