J2EE Interview Questions Part2

7. 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.

8. 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.

9. How many development roles are involved in J2EE application?

There are at least 5 roles involved:

0. Enterprise Bean Developer

 Writes and compiles the source code

 Specifies the deployment descriptor

 Bundles the .class files and deployment descriptor into an EJB JAR file

1. Web Component Developer

 Writes and compiles servlet source code

 Writes JSP and HTML files

 Specifies the deployment descriptor for the Web component

 Bundles the .class, .jsp, .html, and deployment descriptor files in the WAR file

2. J2EE Application Client Developer

 Writes and compiles the source code

 Specifies the deployment descriptor for the client

 Bundles the .class files and deployment descriptor into the JAR file

3. Application Assembler

The application assembler is the company or person who receives application component JAR files from component providers and assembles them into a J2EE application EAR file. The assembler or deployer can edit the deployment descriptor directly or use tools that correctly add XML tags according to interactive selections. A software developer performs the following tasks to deliver an EAR file containing the J2EE application:

 Assembles EJB JAR and WAR files created in the previous phases into a J2EE application (EAR) file

 Specifies the deployment descriptor for the J2EE application

 Verifies that the contents of the EAR file are well formed and comply with the J2EE specification

4. Application Deployer and Administrator

 Configures and deploys the J2EE application

 Resolves external dependencies

 Specifies security settings & attributes

 Assigns transaction attributes and sets transaction controls

 Specifies connections to databases

 Deploys or installs the J2EE application EAR file into the J2EE server

 Administers the computing and networking infrastructure where J2EE applications run

 Oversees the runtime environment

But a developer role depends on the job assignment. For a small company, one developer may take these 5 roles altogether.