J2EE Interview questions and answers

81. What is EJB object 

An object whose class implements the enterprise bean's
remote interface. A client never references an
enterprise bean instance directly; a client always
references an EJB object. The class of an EJB object
is generated by a container's deployment tools. 

82. What is EJB server 

Software that provides services to an EJB container.
For example, an EJB container typically relies on a
transaction manager that is part of the EJB server to
perform the two-phase commit across all the
participating resource managers. The J2EE architecture
assumes that an EJB container is hosted by an EJB
server from the same vendor, so it does not specify
the contract between these two entities. An EJB server
can host one or more EJB containers. 


83. What is EJB server provider 

A vendor that supplies an EJB server. 

83. What is EJB server provider 

What is element 

A unit of XML data, delimited by tags. An XML element
can enclose other elements. 

84. What is empty tag 

A tag that does not enclose any content

85. What is enterprise bean 

A J2EE component that implements a business task or
business entity and is hosted by an EJB container;
either an entity bean, a session bean, or a
message-driven bean. 


86. What is enterprise bean provider 

An application developer who produces enterprise bean
classes, remote and home interfaces, and deployment
descriptor files, and packages them in an EJB JAR
file. 

87. What is enterprise information system 

The applications that constitute an enterprise's
existing system for handling companywide information.
These applications provide an information
infrastructure for an enterprise. An enterprise
information system offers a well-defined set of
services to its clients. These services are exposed to
clients as local or remote interfaces or both.
Examples of enterprise information systems include
enterprise resource planning systems, mainframe
transaction processing systems, and legacy database
systems. 


88. What is enterprise information system resource 

An entity that provides enterprise information
system-specific functionality to its clients. Examples
are a record or set of records in a database system, a
business object in an enterprise resource planning
system, and a transaction program in a transaction
processing system. 

89. What is Enterprise JavaBeans (EJB) 

A component architecture for the development and
deployment of object-oriented, distributed,
enterprise-level applications. Applications written
using the Enterprise JavaBeans architecture are
scalable, transactional, and secure. 

90. What is Enterprise JavaBeans Query Language (EJB
QL) 

Defines the queries for the finder and select methods
of an entity bean having container-managed
persistence. A subset of SQL92, EJB QL has extensions
that allow navigation over the relationships defined
in an entity bean's abstract schema.