J2EE Interview Questions And Answers _ 7

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J2EE Interview Questions And Answers

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 Java Server 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.

What is OASIS ?
Organization for the Advancement of Structured Information Standards. A consortium that drives the development, convergence, and adoption of e-business standards.

What is OMG ?
Object Management Group. A consortium that produces and maintains computer industry specifications for interoperable enterprise applications.

What is one-way messaging ?
A method of transmitting messages without having to block until a response is received.

What is ORB ?
Object request broker. A library that enables CORBA objects to locate and communicate with one another.

What is OS principal ?
A principal native to the operating system on which the J2EE platform is executing.

What is OTS ?
Object Transaction Service. A definition of the interfaces that permit CORBA objects to participate in transactions.

What is parameter entity ?
An entity that consists of DTD specifications, as distinct from a general entity. A parameter entity defined in the DTD can then be referenced at other points, thereby eliminating the need to recode the definition at each location it is used.

What is parsed entity ?
A general entity that contains XML and therefore is parsed when inserted into the XML document, as opposed to an unparsed entity.

What is parser ?
A module that reads in XML data from an input source and breaks it into chunks so that your program knows when it is working with a tag, an attribute, or element data. A nonvalidating parser ensures that the XML data is well formed but does not verify that it is valid. See also validating parser.

What is passivation ?
The process of transferring an enterprise bean from memory to secondary storage. See activation.

What is persistence ?
The protocol for transferring the state of an entity bean between its instance variables and an underlying database.

What is persistent field ?
A virtual field of an entity bean that has container-managed persistence; it is stored in a database.

What is POA ?
Portable Object Adapter. A CORBA standard for building server-side applications that are portable across heterogeneous ORBs.

What is point-to-point messaging system ?
A messaging system built on the concept of message queues. Each message is addressed to a specific queue; clients extract messages from the queues established to hold their messages.

What is primary key ?
An object that uniquely identifies an entity bean within a home.

What is principal ?
The identity assigned to a user as a result of authentication.

What is privilege ?
A security attribute that does not have the property of uniqueness and that can be shared by many principals.

What is processing instruction ?
Information contained in an XML structure that is intended to be interpreted by a specific application.

What is programmatic security ?
Security decisions that are made by security-aware applications. Programmatic security is useful when declarative security alone is not sufficient to express the security model of an application.

What is prolog ?
The part of an XML document that precedes the XML data. The prolog includes the declaration and an optional DTD.

What is public key certificate ?
Used in client-certificate authentication to enable the server, and optionally the client, to authenticate each other. The public key certificate is the digital equivalent of a passport. It is issued by a trusted organization, called a certificate authority, and provides identification for the bearer.

What is publish/subscribe messaging system ?
A messaging system in which clients address messages to a specific node in a content hierarchy, called a topic. Publishers and subscribers are generally anonymous and can dynamically publish or subscribe to the content hierarchy. The system takes care of distributing the messages arriving from a node's multiple publishers to its multiple subscribers.

What is query string ?
A component of an HTTP request URL that contains a set of parameters and values that affect the handling of the request.