Java Enterprise Edition (J2EE/JEE) Interview Questions And Answers

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 multitiered, web-based applications.

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

1. Application client module
2. Web module
3. Enterprise JavaBeans module
4. Resource adapter module

The web module contains:
--JSP files,
--class files for servlets,
--GIF and HTML files, and
--a Web deployment descriptor.
Web modules are packaged as JAR files with a .war (Web ARchive) extension.

The Session bean and Entity bean are two main parts of EJB container.
Session Bean
--represents a workflow on behalf of a client
--one-to-one logical mapping to a client.
--created and destroyed by a client
--not permanent objects
--lives its EJB container(generally) does not survive system shut down
--two types: stateless and stateful beans
Entity Bean
--represents persistent data and behavior of this data
--can be shared among multiple clients
--persists across multiple invocations
--findable permanent objects
--outlives its EJB container, survives system shutdown
--two types: container managed persistence(CMP) and bean managed persistence(BMP)

A container that includes support for the applet programming model.

A first-tier J2EE client component that executes in its own Java virtual machine. Application clients have access to some J2EE platform APIs.

A software unit that consists of one or more classes and an application client deployment descriptor.

An XML file used to configure resources for a JavaServer Faces application, to define navigation rules for the application, and to register converters, validators, listeners, renderers, and components with the application.

A Java-based build tool that can be extended using Java classes. The configuration files are XML-based, calling out a target tree where various tasks get executed.

An authorization rule that determines who is permitted to access a Web resource collection.

A JavaBeans component that corresponds to a JSP page that includes JavaServer Faces components. The backing bean defines properties for the components on the page and methods that perform processing for the component. This processing includes event handling, validation, and processing associated with navigation.

The mechanism whereby data transfer between an entity bean's variables and a resource manager is managed by the entity bean.

Generating the code needed to process a well-defined portion of XML data.

The XML file that contains one or more asant targets. A target is a set of tasks you want to be executed. When starting asant, you can select which targets you want to have executed. When no target is given, the project's default target is executed.

A method of an enterprise bean that implements the business logic or rules of an application.

Same as caller principal.

A deletion that triggers another deletion. A cascade delete can be specified for an entity bean that has container-managed persistence.

A standard extension mechanism for containers that provides connectivity to enterprise information systems. A connector is specific to an enterprise information system and consists of a resource adapter and application development tools for enterprise information system connectivity. The resource adapter is plugged in to a container through its support for system-level contracts defined in the Connector architecture.

The contract between a J2EE component and its container. The contract includes life-cycle management of the component, a context interface that the instance uses to obtain various information and services from its container, and a list of services that every container must provide for its components.

A trusted organization that issues public key certificates and provides identification to the bearer.

The principal that identifies the invoker of the enterprise bean method.

Component methods called by the container to notify the component of important events in its life cycle.

The code that implements the functionality of an application. In the Enterprise JavaBeans architecture, this logic is implemented by the methods of an enterprise bean.

Wiring UI components to back-end data sources such as backing bean properties.