J2EE Interview Questions and Answers
What is EJB Home object ?
An object that provides the life-cycle operations (create, remove, find)
for an enterprise bean. The class for the EJB Home object is generated
by the container's deployment tools. The EJB Home object implements the
enterprise bean's Home interface. The client references an EJB Home
object to perform life-cycle operations on an EJB object. The client
uses JNDI to locate an EJB Home object.
What is EJB JAR file ?
A JAR archive that contains an EJB module.
What is EJB module ?
A deployable unit that consists of one or more enterprise beans and an
EJB deployment descriptor.
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.
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.
What is EJB server provider ?
A vendor that supplies an EJB server.
What is element ?
A unit of XML data, delimited by tags. An XML element can enclose other
What is empty tag ?
A tag that does not enclose any content.
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.
What is enterprise bean provider ?
An application developer who produces enterprise bean classes, remote
and Interview Questions - Home interfaces, and deployment descriptor files, and packages them
in an EJB JAR file.
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
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.
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.
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.
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.
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