J2EE Interview questions and answers

181. What is JSP tag library 

A collection of custom tags described via a tag
library descriptor and Java classes. 

182. What is JSTL 

Abbreviate of JavaServer Pages Standard Tag Library. 

183. What is JTA 

Abbreviate of Java Transaction API. 


184. What is JTS 

Abbreviate of Java Transaction Service. 

185. What is keystore 

A file containing the keys and certificates used for
authentication 


186. 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. 




187. 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. 

188. What is local subset 

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

189. What is managed bean creation facility 

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

190. 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.