J2EE Interview questions and answers

91. What is an entity 

A distinct, individual item that can be included in an
XML document by referencing it. Such an entity
reference can name an entity as small as a character
(for example, <, which references the less-than symbol
or left angle bracket, <). An entity reference can
also reference an entire document, an external entity,
or a collection of DTD definitions. 

92. What is entity bean 

An enterprise bean that represents persistent data
maintained in a database. An entity bean can manage
its own persistence or can delegate this function to
its container. An entity bean is identified by a
primary key. If the container in which an entity bean
is hosted crashes, the entity bean, its primary key,
and any remote references survive the crash. 


93. What is entity reference 

A reference to an entity that is substituted for the
reference when the XML document is parsed. It can
reference a predefined entity such as < or reference
one that is defined in the DTD. In the XML data, the
reference could be to an entity that is defined in the
local subset of the DTD or to an external XML file (an
external entity). The DTD can also carve out a segment
of DTD specifications and give it a name so that it
can be reused (included) at multiple points in the DTD
by defining a parameter entity. 

94. What is error 

A SAX parsing error is generally a validation error;
in other words, it occurs when an XML document is not
valid, although it can also occur if the declaration
specifies an XML version that the parser cannot
handle. See also fatal error, warning. 

95. What is Extensible Markup Language 

XML. 

96. What is external entity 

An entity that exists as an external XML file, which
is included in the XML document using an entity
reference. 





96. What is external subset 

That part of a DTD that is defined by references to
external DTD files.

97. What is fatal error 

A fatal error occurs in the SAX parser when a document
is not well formed or otherwise cannot be processed.
See also error, warning. 

98. What is filter 

An object that can transform the header or content (or
both) of a request or response. Filters differ from
Web components in that they usually do not themselves
create responses but rather modify or adapt the
requests for a resource, and modify or adapt responses
from a resource. A filter should not have any
dependencies on a Web resource for which it is acting
as a filter so that it can be composable with more
than one type of Web resource. 




99. What is filter chain 

A concatenation of XSLT transformations in which the
output of one transformation becomes the input of the
next. 

100. What is finder method 

A method defined in the home interface and invoked by
a client to locate an entity bean.