Sunday, May 23

Java Fundamental-X

1. What is J2EE Connector?
The J2EE Connector API is used by J2EE tools vendors and system integrators to create resource adapters that support access to enterprise information systems that can be plugged into any J2EE product. Each type of database or EIS has a different resource adapter.

2. What is JAAP?
The Java Authentication and Authorization Service (JAAS) provide a way for a J2EE application to authenticate and authorize a specific user or group of users to run it. It is a standard Pluggable Authentication Module (PAM) framework that extends the Java 2 platform security architecture to support user-based authorization.

3. What is Model 1?
Using JSP technology alone to develop Web page. Such term is used in the earlier JSP specification. Model 1 architecture is suitable for applications that have very simple page flow, have little need for centralized security control or logging, and change little over time. Model 1 applications can often be refactored to Model 2 when application requirements change.

4. What is Model 2?
Using JSP and Servlet together to develop Web page. Model 2 applications are easier to maintain and extend, because views do not refer to each other directly.

5. What is Struts?
A Web page development framework. Struts combine Java Servlets, Java Server Pages, custom tags, and message resources into a unified framework. It is a cooperative, synergistic platform, suitable for development teams, independent developers, and everyone between.

6. How is the MVC design pattern used in Struts framework?
In the MVC design pattern, application flow is mediated by a central Controller. The Controller delegates requests to an appropriate handler. The handlers are tied to a Model, and each handler acts as an adapter between the request and the Model. The Model represents, or encapsulates, an application's business logic or state. Control is usually then forwarded back through the Controller to the appropriate View. The forwarding can be determined by consulting a set of mappings, usually loaded from a database or configuration file. This provides a loose coupling between the View and Model, which can make an application significantly easier to create and maintain.
Controller--Servlet controller which supplied by Struts itself; View --- what you can see on the screen, a JSP page and presentation components; Model --- System state and a business logic JavaBeans.

7. What does web module contain?
The web module contains:
o JSP files,
o class files for Servlets,
o GIF and HTML files, and
o A Web deployment descriptor.
Web modules are packaged as JAR files with a .war (Web Archive) extension.

8. What APIs are available for developing a J2EE application?
o Enterprise JavaBeans Technology(3 beans: Session Beans, Entity Beans and Message-Driven Beans)
o JDBC API(application level interface and service provider interface or driver)
o Java Servlets Technology(Servlet)
o Java ServerPage Technology(JSP)
o Java Message Service(JMS)
o Java Naming and Directory Interface(JNDI)
o Java Transaction API(JTA)
o JavaMail API
o JavaBeans Activation Framework(JAF used by JavaMail)
o Java API for XML Processing(JAXP,SAX, DOM, XSLT)
o Java API for XML Registries(JAXR)
o Java API for XML-Based RPC(JAX-RPC)-SOAP standard and HTTP
o SOAP with Attachments API for Java(SAAJ)-- low-level API upon which JAX-RPC depends
o J2EE Connector Architecture
o Java Authentication and Authorization Service(JAAS)

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