J2EE Interview Questions and Answers 20

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.

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

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.

What is virtual host ?
Multiple hosts plus domain names mapped to a single IP address.

What is W3C ?
World Wide Web Consortium. The international body that governs Internet standards. Its Web site is http://www.w3.org/.

What is WAR file ?
Web application archive file. A JAR archive that contains a Web module.

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.

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.

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.

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

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.

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.

What is Web container provider ?
A vendor that supplies a Web container.

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.

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

What is Web resource collection ?
A list of URL patterns and HTTP methods that describe a set of Web resources to be protected.