J2EE Interview questions and answers

191. What is message consumer

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

192. 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.



193. What is message producer

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

194. 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 (*).



195. 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.

196. What is method permission

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

197. What is mutual authentication

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



198. 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.

199. What is naming context

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

200. 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.