J2EE Interview Questions with Answers Page III

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What is form-based authentication?

An authentication mechanism in which a Web container provides an application-specific form for logging in. This form of authentication uses Base64

encoding and can expose user names and passwords unless all connections are over SSL.

What is general entity?

An entity that is referenced as part of an XML document's content, as distinct from a parameter entity, which is referenced in the DTD. A general entity

can be a parsed entity or an unparsed entity.

What is group?

An authenticated set of users classified by common traits such as job title or customer profile. Groups are also associated with a set of roles, and

every user that is a member of a group inherits all the roles assigned to that group.

What is handle?

An object that identifies an enterprise bean. A client can serialize the handle and then later deserialize it to obtain a reference to the enterprise

bean.

What is home handle?

An object that can be used to obtain a reference to the home interface. A home handle can be serialized and written to stable storage and deserialized

to obtain the reference.

What is home interface?

One of two interfaces for an enterprise bean. The home interface defines zero or more methods for managing an enterprise bean. The home interface of a

session bean defines create and remove methods, whereas the home interface of an entity bean defines create, finder, and remove methods.

What is IDL?

Interface Definition Language. A language used to define interfaces to remote CORBA objects. The interfaces are independent of operating systems and

programming languages.

What is IIOP?

Internet Inter-ORB Protocol. A protocol used for communication between CORBA object request brokers.

What is impersonation?

An act whereby one entity assumes the identity and privileges of another entity without restrictions and without any indication visible to the

recipients of the impersonator's calls that delegation has taken place. Impersonation is a case of simple delegation.

What is initialization parameter?

A parameter that initializes the context associated with a servlet.

What is ISO 3166?

The international standard for country codes maintained by the International Organization for Standardization (ISO).

What is ISV?

Independent software vendor.

What is J2EE application?

Any deployable unit of J2EE functionality. This can be a single J2EE module or a group of modules packaged into an EAR file along with a J2EE

application deployment descriptor. J2EE applications are typically engineered to be distributed across multiple computing tiers.

What is J2EE component?

A self-contained functional software unit supported by a container and configurable at deployment time. The J2EE specification defines the following

J2EE components: Application clients and applets are components that run on the client. Java servlet and JavaServer Pages (JSP) technology components

are Web components that run on the server. Enterprise JavaBeans (EJB) components (enterprise beans) are business components that run on the server.

J2EE components are written in the Java programming language and are compiled in the same way as any program in the language. The difference between

J2EE components and "standard" Java classes is that J2EE components are assembled into a J2EE application, verified to be well formed and in compliance

with the J2EE specification, and deployed to production, where they are run and managed by the J2EE server or client container.

What is J2EE module?

A software unit that consists of one or more J2EE components of the same container type and one deployment descriptor of that type. There are four

types of modules: EJB, Web, application client, and resource adapter. Modules can be deployed as stand-alone units or can be assembled into a J2EE

application.

What is J2EE product?

An implementation that conforms to the J2EE platform specification.

What is J2EE product provider?

A vendor that supplies a J2EE product.

What is J2EE server?

The runtime portion of a J2EE product. A J2EE server provides EJB or Web containers or both.

What is JAR?

Java archive. A platform-independent file format that permits many files to be aggregated into one file.

What is Java API for XML Processing (JAXP)?

An API for processing XML documents. JAXP leverages the parser standards SAX and DOM so that you can choose to parse your data as a stream of events or

to build a tree-structured representation of it. JAXP supports the XSLT standard, giving you control over the presentation of the data and enabling you

to convert the data to other XML documents or to other formats, such as HTML. JAXP provides namespace support, allowing you to work with schema that

might otherwise have naming conflicts.

What is Java API for XML Registries (JAXR)?

An API for accessing various kinds of XML registries.

What is Java API for XML-based RPC (JAX-RPC)?

An API for building Web services and clients that use remote procedure calls and XML.

What is Java IDL?

A technology that provides CORBA interoperability and connectivity capabilities for the J2EE platform. These capabilities enable J2EE applications to

invoke operations on remote network services using the Object Management Group IDL and IIOP.

What is Java Message Service (JMS)?

An API for invoking operations on enterprise messaging systems.

What is keystore?

A file containing the keys and certificates used for authentication

What is life cycle (J2EE component)?

The framework events of a J2EE component's existence. Each type of component has defining events that mark its transition into states in which it has

varying availability for use. For example, a servlet is created and has its init method called by its container before invocation of its service method

by clients or other servlets that require its functionality. After the call of its init method, it has the data and readiness for its intended use. The

servlet's destroy method is called by its container before the ending of its existence so that processing associated with winding up can be done and

resources can be released. The init and destroy methods in this example are callback methods. Similar considerations apply to the life cycle of all

J2EE component types: enterprise beans, Web components (servlets or JSP pages), applets, and application clients.

What is life cycle (JavaServer Faces)?

A set of phases during which a request for a page is received, a UI component tree representing the page is processed, and a response is produced.

During the phases of the life cycle: The local data of the components is updated with the values contained in the request parameters. Events generated

by the components are processed. Validators and converters registered on the components are processed. The components' local data is updated to

back-end objects. The response is rendered to the client while the component state of the response is saved on the server for future requests.

What is local subset?

That part of the DTD that is defined within the current XML file.

What is managed bean creation facility?

A mechanism for defining the characteristics of JavaBeans components used in a JavaServer Faces application.

What is message?

In the Java Message Service, an asynchronous request, report, or event that is created, sent, and consumed by an enterprise application and not by a

human. It contains vital information needed to coordinate enterprise applications, in the form of precisely formatted data that describes specific

business actions.

What is message consumer?

An object created by a JMS session that is used for receiving messages sent to a destination.

What is message-driven bean?

An enterprise bean that is an asynchronous message consumer. A message-driven bean has no state for a specific client, but its instance variables can

contain state across the handling of client messages, including an open database connection and an object reference to an EJB object. A client accesses

a message-driven bean by sending messages to the destination for which the bean is a message listener.

What is message producer?

An object created by a JMS session that is used for sending messages to a destination.

What is mixed-content model?

A DTD specification that defines an element as containing a mixture of text and one more other elements. The specification must start with #PCDATA,

followed by diverse elements, and must end with the "zero-or-more" asterisk symbol (*).

What is method-binding expression?

A JavaServer Faces EL expression that refers to a method of a backing bean. This method performs either event handling, validation, or navigation

processing for the UI component whose tag uses the method-binding expression.

What is method permission?

An authorization rule that determines who is permitted to execute one or more enterprise bean methods.

What is mutual authentication?

An authentication mechanism employed by two parties for the purpose of proving each other's identity to one another.

What is namespace?

A standard that lets you specify a unique label for the set of element names defined by a DTD. A document using that DTD can be included in any other

document without having a conflict between element names. The elements defined in your DTD are then uniquely identified so that, for example, the

parser can tell when an element should be interpreted according to your DTD rather than using the definition for an element in a different DTD.

What is naming context?

A set of associations between unique, atomic, people-friendly identifiers and objects.

What is naming environment?

A mechanism that allows a component to be customized without the need to access or change the component's source code. A container implements the

component's naming environment and provides it to the component as a JNDI naming context. Each component names and accesses its environment entries

using the java:comp/env JNDI context. The environment entries are declaratively specified in the component's deployment descriptor.

What is normalization?

The process of removing redundancy by modularizing, as with subroutines, and of removing superfluous differences by reducing them to a common

denominator. For example, line endings from different systems are normalized by reducing them to a single new line, and multiple whitespace characters

are normalized to one space.

What is North American Industry Classification System (NAICS)?

A system for classifying business establishments based on the processes they use to produce goods or services.

What is notation?

A mechanism for defining a data format for a non-XML document referenced as an unparsed entity. This is a holdover from SGML. A newer standard is to

use MIME data types and namespaces to prevent naming conflicts.