Sunday, May 2

Java Fundamental-VIII

1. What is J2EE?
J2EE is an environment for developing and deploying enterprise applications. The J2EE platform consists of a set of services, application programming interfaces (APIs), and protocols that provide the functionality for developing multi tiered, and web-based applications.

2. What is the J2EE module?
A J2EE module consists of one or more J2EE components for the same container type and one component deployment descriptor of that type.

3. What are the components of J2EE application?
A J2EE component is a self-contained functional software unit that is assembled into a J2EE application with its related classes and files and communicates with other components. The J2EE specification defines the following J2EE components:
o Application clients and applets are client components.
o Java Servlets and Java Server Pages TM (JSPTM) technology components are web components.
o Enterprise JavaBeansTM (EJBTM) components (enterprise beans) are business components.
o Resource adapter components provided by EIS and tool vendors.

4. What are the four types of J2EE modules?
1. Application client module
2. Web module
3. Enterprise JavaBeans module
4. Resource adapter module

5. What does application client module contain?
The application client module contains:
o class files,
o an application client deployment descriptor.
Application client modules are packaged as JAR files with a .jar extension.

6. What does Enterprise JavaBeans module contain?
The Enterprise JavaBeans module contains:
o class files for enterprise beans
o An EJB deployment descriptor.
EJB modules are packaged as JAR files with a .jar extension.

7. What does resource adapt module contain?
The resource adapt module contains:
o all Java interfaces,
o classes,
o native libraries,
o other documentation,
o A resource adapter deployment descriptor.
Resource adapter modules are packages as JAR files with a .rar (Resource adapter Archive) extension.

8. Is J2EE application only a web-based?
NO. A J2EE application can be web-based or non-web-based. If an application client executes on the client machine, it is a non-web-based J2EE application. The J2EE application can provide a way for users to handle tasks such as J2EE system or application administration. It typically has a graphical user interface created from Swing or AWT APIs, or a command-line interface. When user request, it can open an HTTP connection to establish communication with a Servlet running in the web tier.

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