J2EE Interview questions and answers

311. What is Web component

A component that provides services in response to
requests; either a servlet or a JSP page.

312. What is Web container

A container that implements the Web component contract
of the J2EE architecture. This contract specifies a
runtime environment for Web components that includes
security, concurrency, life-cycle management,
transaction, deployment, and other services. A Web
container provides the same services as a JSP
container as well as a federated view of the J2EE
platform APIs. A Web container is provided by a Web or
J2EE server.



313. What is Web container, distributed

A Web container that can run a Web application that is
tagged as distributable and that executes across
multiple Java virtual machines running on the same
host or on different hosts.

314. What is Web container provider

A vendor that supplies a Web container.

315. What is Web module

A deployable unit that consists of one or more Web
components, other resources, and a Web application
deployment descriptor contained in a hierarchy of
directories and files in a standard Web application
format.

316. What is Web resource

A static or dynamic object contained in a Web
application that can be referenced by a URL.



317. What is Web resource collection

A list of URL patterns and HTTP methods that describe
a set of Web resources to be protected.

318. What is Web server

Software that provides services to access the
Internet, an intranet, or an extranet. A Web server
hosts Web sites, provides support for HTTP and other
protocols, and executes server-side programs (such as
CGI scripts or servlets) that perform certain
functions. In the J2EE architecture, a Web server
provides services to a Web container. For example, a
Web container typically relies on a Web server to
provide HTTP message handling. The J2EE architecture
assumes that a Web container is hosted by a Web server
from the same vendor, so it does not specify the
contract between these two entities. A Web server can
host one or more Web containers.



319. What is Web server provider

A vendor that supplies a Web server.

320. What is Web service

An application that exists in a distributed
environment, such as the Internet. A Web service
accepts a request, performs its function based on the
request, and returns a response. The request and the
response can be part of the same operation, or they
can occur separately, in which case the consumer does
not need to wait for a response. Both the request and
the response usually take the form of XML, a portable
data-interchange format, and are delivered over a wire
protocol, such as HTTP.

J2EE Interview questions and answers

301. What is user (security)

An individual (or application program) identity that
has been authenticated. A user can have a set of roles
associated with that identity, which entitles the user
to access all resources protected by those roles.

302. What is user (security)

A valid XML document, in addition to being well
formed, conforms to all the constraints imposed by a
DTD. It does not contain any tags that are not
permitted by the DTD, and the order of the tags
conforms to the DTD's specifications.



303. What is validating parser

A parser that ensures that an XML document is valid in
addition to being well formed. See also parser.

304. What is value-binding _expression

A JavaServer Faces EL _expression that refers to a
property of a backing bean. A component tag uses this
_expression to bind the associated component's value or
the component instance to the bean property. If the
component tag refers to the property via its value
attribute, then the component's value is bound to the
property. If the component tag refers to the property
via its binding attribute then the component itself is
bound to the property.

305. What is virtual host

Multiple hosts plus domain names mapped to a single IP
address.

306. What is W3C

World Wide Web Consortium. The international body that
governs Internet standards. Its Web site is
http://www.w3.org/.

307. What is WAR file

Web application archive file. A JAR archive that
contains a Web module.



308. What is warning

A SAX parser warning is generated when the document's
DTD contains duplicate definitions and in similar
situations that are not necessarily an error but which
the document author might like to know about, because
they could be. See also fatal error, error.

309. What is Web application

An application written for the Internet, including
those built with Java technologies such as JavaServer
Pages and servlets, as well as those built with
non-Java technologies such as CGI and Perl.



310. What is Web application, distributable

A Web application that uses J2EE technology written so
that it can be deployed in a Web container distributed
across multiple Java virtual machines running on the
same host or different hosts. The deployment
descriptor for such an application uses the
distributable element.