J2EE Interview questions and answers

281. What is servlet container 

A container that provides the network services over
which requests and responses are sent, decodes
requests, and formats responses. All servlet
containers must support HTTP as a protocol for
requests and responses but can also support additional
request-response protocols, such as HTTPS. 

282. What is servlet container, distributed 

A servlet 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. 


283. What is servlet context 

An object that contains a servlet's view of the Web
application within which the servlet is running. Using
the context, a servlet can log events, obtain URL
references to resources, and set and store attributes
that other servlets in the context can use. 

284. What is servlet mapping 

Defines an association between a URL pattern and a
servlet. The mapping is used to map requests to
servlets. 

285. What is session 

An object used by a servlet to track a user's
interaction with a Web application across multiple
HTTP requests. 

286. What is session bean 

An enterprise bean that is created by a client and
that usually exists only for the duration of a single
client-server session. A session bean performs
operations, such as calculations or database access,
for the client. Although a session bean can be
transactional, it is not recoverable should a system
crash occur. Session bean objects either can be
stateless or can maintain conversational state across
methods and transactions. If a session bean maintains
state, then the EJB container manages this state if
the object must be removed from memory. However, the
session bean object itself must manage its own
persistent data. 


287. What is SGML 

Standard Generalized Markup Language. The parent of
both HTML and XML. Although HTML shares SGML's
propensity for embedding presentation information in
the markup, XML is a standard that allows information
content to be totally separated from the mechanisms
for rendering that content. 

288. What is SOAP 

Simple Object Access Protocol. A lightweight protocol
intended for exchanging structured information in a
decentralized, distributed environment. It defines,
using XML technologies, an extensible messaging
framework containing a message construct that can be
exchanged over a variety of underlying protocols. 


289. What is SOAP with Attachments API for Java (SAAJ)


The basic package for SOAP messaging, SAAJ contains
the API for creating and populating a SOAP message. 

290. What is SQL 

Structured Query Language. The standardized relational
database language for defining database objects and
manipulating data.