QB - Jayaram College of Engineering and Technology

Estd: 1994
JAYARAM
COLLEGE OF ENGINEERING AND
TECHNOLOGY
Pagalavadi, Tiruchirappalli - 621014
(An approved by AICTE and Affiliated to Anna University)
Department of Information Technology
Subject code : IT1402 Year/Sem: IV/VII
ISO 9001:2000
Certified
Subject Name : Middleware Technologies Faculty
Incharge: Mr.R.Palanikumar
UNIT I
1. What is CORBA
CORBA stands for the common object request broker Architecture. It is a
set of standard mechanisms for naming, locating and defining objects in a
distributed computing environment.
2. What is a database server
With a database server, the client passes SQL requests as messages to
the database server. The results of each SQL command are returned over
the network. The server uses its own processing power to find the request
data instead data instead of processing all the records back to the client
and then getting if find its own data. The result is a much more efficient
use of distributed processing power. It is also known as SQL engine.
3. What is File Server
File servers are useful for sharing files across a network with a file server,
the client passes requests for file records over network to file server.
4. What is web server
This new model of Client/Server consists of thin,portable, universal clients
that talk to super fat servers. In the simplest form, a web server returns
document when clients ask for them by name. the clients and server
communicating using an RPC Like protocol called HTTP.
Department of IT, JCET, Trichy. Page 1

5. What is meant by 2 tier architecture
In 2 tier client server systems, the application logic is either buried inside
the user interface on the client or within the database on the server.
Example : file servers and database servers with stored procedures.
6. What is meant by Middleware
Middleware is distributed software needed to support interaction between
clients and server. In short, it is the software that is in the middle of the
client/server systems and It acts as a bridge between the clients and
server. It starts with the API set on the client side that is used to invoke a
service and it covers the transmission of the request over the network
and the resulting response. It neither includes the software that provides
the actual service that is in the servers domain not the user interface or
the application login that’s in clients domain.
7. What are the two board classes of middleware
General middleware
Service specific middleware
8. What is group ware Server
Group server addresses the management of semi-structured information
such as text, image, tesmail, bulletin boards and the flow of work. These
client/server systems have people in direct contact with other people.
9. What are the characteristics of client /Server
Service
Shared resources
Asymmentrical protocols
Transparency of location
Mix and match
Message based exchanges
Encapsulation of services
Scalability
Integrity
Department of IT, JCET, Trichy. Page 2

Client /server computing is the ultimate open platform it gives the freedom
to mix and match components of almost any level. Clients and servers are
loosely coupled systems that interact through a message passing
mechanism.
10. What is ACID Property
ACID is a term coined by Andrew Reuter in 1983, which stands for
atomicity, consistence, isolation and durability.
11. What are the classifications of clients
Non GUI clients – two types are
Non GUI clients that do not need multi tasking
(Example automatic teller machines, cell phone)
Non GUI Clients that need multi tasking
Example ROBOTs
GUI clients
OOUI clients
12. What are stored procedures
A stored procedures is a named collection of SQL statements and
procedural logic that is complied verified and stored in a sever database. It
is typically treated like any other database object. Stored procedures
accept input parameters so that a single procedure can be used over the
network by multiple clients using different input data. A single remote
message triggers the execution of a collection of stored SQL statements.
The results are a reduction of network traffic and better performance.
13. What are the five major technologies that can be used to create
client/server applications
Database Servers
TP monitors
Groupware
Distributed objects
Intranets
Department of IT, JCET, Trichy. Page 3

14.What is meant by Mix and match
The ideal client server software is independent of hardware and operating
system software platform. It should be able to mix match client and server
platforms.
15. What is a Transaction server
With a transaction server, the client invokes remote procedures that reside
on the server with an SQL database engine. These remote procedures on
the server execute a group of SQL statements. The network exchange
consists of a single request reply message. The SQL statements either all
succeed or fail as a unit.
16. What is an object server
With an object server, the client server application is written as a set of
communicating objects. Client object commnunicate with server objects
using an object request broker. The client invokes a method on a remote
object. The ORB locates an instance of that object server class, invokes
the requested method and returns the results to the client object. Server
objects must provide support for concurrency and sharing. The ORB
brings it all together.
17. What are the called fat clients and fat servers
If the bulk of the application runs on the client side, then it is fat clients, it
is used for decision support and personal software. If the bulk of the
application runs on the server side, then it is fat servers. It tries to
minimize network interchanges by creating more abstract levels of
services.
18. What is message oriented middleware
MOM allows general purpose messages to be exchanged in a
client/server system using message queues. Application communicate
over networks by simply putting messages in the queues and getting
messages form queue. It typically provides and server can run at different
times. It is a post office like metaphor.
Department of IT, JCET, Trichy. Page 4

19. What is structured query language (SQL)
SQL is a powerful set oriented language which was developed by ibm
research for the databases that adhere to the relational model. It consists
of a short list of powerful, yet highly flexible commands that can be used to
manipulate information collected in tables. Through SQL. We can
manipulate and control sets of record sets a time.
20. What are the three types of SQL database server architectuer
Process per client architecture. Example oracle6, Informix)
Multithreaded architecture. Example Sybase, SQL server)
Hybrid architecture example oracle
UNIT I
BIG QUESTIONS
1. Explain the architecture of MOM How is it different from other types of
Middleware.
2. Define Middleware and types of middleware in detail.
3. How is RPC implemented in client server environment Explain in detail the
various issues involved while implementing with diagram.
4. How are the servers classified Describe each type in detail.
5. What are the most typical functional units of the client /server applications
Department of IT, JCET, Trichy. Page 5

UNIT II
1. What is EJB
EJB stands for Enterprise JavaBeans and is widely-adopted server side
component architecture for J2EE. It enables rapid development of ission-critical
application that are versatile, reusable and portable across middleware while
protecting IT investment and preventing vendor lock-in.
2. What is session Facade
Session Facade is a design pattern to access the Entity bean through local
interface than accessing directly. It increases the performance over the network.
In this case we call session bean which on turn call entity bean.
3. What is EJB role in J2EE
EJB technology is the core of J2EE. It enables developers to write reusable and
portable server-side business logic for the J2EE platform.
4. What is the difference between EJB and Java beans
EJB is a specification for J2EE server, not a product; Java beans may be a
graphical component in IDE.
5. What are the key features of the EJB technology
1. EJB components are server-side components written entirely in the Java
programming language
2. EJB components contain business logic only - no system-level
programming & services, such as transactions, security, life-cycle,
threading, persistence, etc. are automatically managed for the EJB
component by the EJB server.
3. EJB architecture is inherently transactional, distributed, portable multi-tier,
scalable and secure.
4. EJB components are fully portable across any EJB server and any OS.
5. EJB architecture is wire-protocol neutral--any protocol can be utilized like
IIOP, JRMP, HTTP, DCOM, etc.
Department of IT, JCET, Trichy. Page 6

6. What are the key benefits of the EJB technology
1. Rapid application development
2. Broad industry adoption
3. Application portability
4. Protection of IT investment
7. How many enterprise beans
There are three kinds of enterprise beans:
1. session beans,
2. entity beans, and
3. message-driven beans.
8. What is message-driven bean
A message-driven bean combines features of a session bean and a Java
Message Service (JMS) message listener, allowing a business component to
receive JMS. A message-driven bean enables asynchronous clients to access
the business logic in the EJB tier.
9. How can I call one EJB from inside of another EJB
EJBs can be clients of other EJBs. It just works. Use JNDI to locate the Home
Interface of the other bean, then acquire an instance reference, and so forth.
10. Can a Session Bean be defined without ejbCreate() method
The ejbCreate() methods is part of the bean's lifecycle, so, the compiler will not
return an error because there is no ejbCreate() method.
However, the J2EE spec is explicit:
the home interface of a Stateless Session Bean must have a single
create() method with no arguments, while the session bean class must
contain exactly one ejbCreate() method, also without arguments.
Stateful Session Beans can have arguments (more than one create
method)
Department of IT, JCET, Trichy. Page 7

11. Why would a session bean use bean-managed transactions
In some situations, it's necessary for a (stateful) session bean to selectively
control which methods participate in transactions, and then take over the
bundling of operations that form a logical unit of work.
12. Is method overloading allowed in EJB
Yes you can overload methods.
13. How can JMS be used from EJB 1.1
The same as any client would use JMS. At this point there is no integration, but it
is planned for a future release of the EJB spec.
14. Can primary keys contain more than one field
Yes, a primary key can have as many fields as the developer feels is necessary,
just make sure that each field you specify as the primary key, you also specify a
matching field in the bean class. A primary key is simply one or more attributes
which uniquely identify a specific element in a database. Also, remember to
account for all fields in the equals() and hashCode() methods.
15. Which fields in beans should be public
All Container Managed Fields in an Entity Bean must be public.
Ejb 1.1 spec section 9.4.1 - "The fields must be defined in the entity bean class
as public, and must not be defined as transient."
16. How do I automatically generate primary keys
A common way to do it is to use a stateless session bean to retrieve the ID that
you wish to use as the primary key. This stateless session bean can then
execute an Oracle sequencer or procedure etc. to retrieve the ID value used as
the primary key.
17 What are the different type of Enterprise JavaBeans
There are 3 types of enterprise beans, namely: Session bean, Entity beans
and Message driven beans.
Department of IT, JCET, Trichy. Page 8

BIG QUESTIONS:
UNIT – II
1. Draw the architecture and explain the functions of various entities
involved.
2. Discuss the roles in EJB.
3. Draw the life cycle of Entity bean and explain
4. List the Constraints on using Session beans.
5. Explain the concept of session bean and It type in detail.
Department of IT, JCET, Trichy. Page 9

Unit III
1. What is Session Bean
Session bean represents a single client inside the J2EE server. To access the
application deployed in the server the client invokes methods on the session
bean. The session bean performs the task shielding the client from the
complexity of the business logic.
Session bean components implement the javax.ejb.SessionBean interface.
Session beans can act as agents modeling workflow or provide access to
special transient business services. Session beans do not normally represent
persistent business concepts. A session bean corresponds to a client server
session. The session bean is created when a client requests some query on
the database and exists as long as the client server session exists.
2. What are different types of session bean
There are two types of session beans, namely: Stateful and Stateless.
3. What is an Entity Bean
An entity bean represents a business object in a persistent storage
mechanism. An entity bean typically represents a table in a relational
database and each instance represents a row in the table. Entity bean differs
from session bean by: persistence, shared access, relationship and primary
key.
4. What are different types of entity beans
There are two types of entity beans available. Container Managed
Persistence (CMP) , Bean managed persistence (BMP).
5. What is abstract schema
In order to generate the data access calls, the container needs information
that you provide in the entity bean's abstract schema. It is a part of Deployment
Descriptor. It is used to define the bean's persistent fields and relation ships.
Department of IT, JCET, Trichy. Page 10

6. When we should use Entity Bean
When the bean represents a business entity, not a procedure. we should
use an entity bean. Also when the bean's state must be persistent we should use
an entity bean. If the bean instance terminates or if the J2EE server is shut down,
the bean's state still exists in persistent storage (a database).
7. When to Use Session Beans
At any given time, only one client has access to the bean instance. The
state of the bean is not persistent, existing only for a short period (perhaps a few
hours). The bean implements a web
service. Under all the above circumstances we can use session beans.
8. When to use Stateful session bean
The bean's state represents the interaction between the bean and a
specific client. The bean needs to hold information about the client across
method invocations. The bean mediates between the client and the other
components of the application, presenting a simplified view to the client. Under
all the above circumstances we can use a stateful session bean.
9. When to use a stateless session bean
The bean's state has no data for a specific client. In a single method
invocation, the bean performs a generic task for all clients. For example, you
might use a stateless session bean to send an email that confirms an online
order. The bean fetches from a database a set of read-only data that is often
used by clients. Such a bean, for example, could retrieve the table rows that
represent the products that are on sale this month. Under all the above
circumstance we can use a stateless session bean.
10. Why Use EJB
EJB helps in building enterprise applications easily. Developers of EJB
needs to focus on business logic only. All other features like transaction,
persistence etc will be managed by the container. EJB provides developers
architectural independence.
Department of IT, JCET, Trichy. Page 11

11. What are the different methods of Entity Bean
An entity bean consists of 4 type of methods: create methods, finder
methods, remove methods and home methods.
12. What is the difference between EJB and Java beans
EJB is a specification for J2EE server, not a product; Java beans may be a
graphical component in IDE.
13. What is EJB role in J2EE
EJB technology is the core of J2EE. It enables developers to write reusable and
portable server-side business logic for the J2EE platform.
14. What are the key benefits of the EJB technology
1. Rapid application development
2. Broad industry adoption
3. Application portability
4. Protection of IT investment
15. How many enterprise beans
There are three kinds of enterprise beans:
1. session beans,
2. entity beans, and
3. Message-driven beans.
16. What is message-driven bean
A message-driven bean combines features of a session bean and a Java
Message Service (JMS) message listener, allowing a business component to
receive JMS. A message-driven bean enables asynchronous clients to access
the business logic in the EJB tier.
17. What is the difference between session and entity beans
An entity bean represents persistent global data from the database; a session
bean represents transient user-specific data that will die when the user
disconnects (ends his session). Generally, the session beans implement
business methods (e.g. Bank.transferFunds) that call entity beans (e.g.
Account.deposit, Account.withdraw)
Department of IT, JCET, Trichy. Page 12

18. How many EJB Objects are created for a Bean
For a Session bean – one EJB object for one bean instance.
For entity bean – it depends , if two users are accessing one row at time then
one EJB object is used for both the beans other wise for each bean one EJB
object.
19. What is EJB container
An EJB container is a run-time environment that manages one or more
enterprise beans. The EJB container manages the life cycles of enterprise bean
objects, coordinates distributed transactions, and implements object security.
Generally, each EJB container is provided by an EJB server and contains a set
of enterprise beans that run on the server.
20. What is the difference between ejbCreate() and ejbPostCreate
The purpose of ejbPostCreate() is to perform clean-up database operations after
SQL INSERTs (which occur when ejbCreate() is called) when working with CMP
entity beans. ejbCreate() is called before database INSERT operations. You
need to use ejbPostCreate() to define operations, like set a flag, after INSERT
completes successfully
UNIT III
BIG QUESTIONS
1. Explain Life Cycle of session bean with diagram.
2. Explain detail about Entity beans and its deployment.
3. (i) Draw the life cycle of entity bean and explain.
(ii) List the constraints on using session beans.
Department of IT, JCET, Trichy. Page 13

UNIT IV
1. Why we need CORBA
It is used to solve one fundamental problem-“how can distributed object oriented
systems implemented in different languages and running on different platforms”
2. What are the essential parts of CORBA
Invocation Interfaces
Object Request Broker
Object Adapters
3. What are the requirements need to work invocation interfaces and object
adapters
All object interfaces need to be described in a common language.
All languages used must have bindings to the common language.
4. What is the use ORB
An ORB is capable of loading and starting an object servant which receiving
invocation requests for an object of that servant.
5. What is responsible of object adapter
An object adapter is responsible for which servant serves telling an ORB which
new object.
6. Differentiate stubs and skeletons.
Sl.no Stubs Skeletons
1.
2.
Called client side proxy objects.
It forwards all invocations through the
ORB to the real target object.
Called server side stubs
It directly invokes the target method.
7. Specify the features of SOM.
Meta programming
Binary compatibility
Department of IT, JCET, Trichy. Page 14

8. Specify any four services supporting enterprise distributed computing.
Naming and trader service.
Event and notification service
Object transaction service
Security service
9. Specify any four services supporting architecture using fine-grained
objects
_ Concurrency control service
_ Licensing service
_ Lifecycle service
_ Relationship service
_ Persistent state service
10. What is naming service
It allows arbitrary names to be associated with an object. Names are unique
within
a naming context and naming contexts from a hierarchy.
11. What is push model
In push model the event supplier calls a push method on the event channel,
which
reacts by calling the push method of all registered consumers.
12. What is pull model
In pull model the consumers call the pull method of the event channel, effectively
pooling the channel for events.
13. What is the life cycle service
This service supports creation, copying, moving and deletion of objects and
related
group of objects.
14. What are the features of CCM components
Ports that are classified into facets, receptacles, event sources and
event sinks.
Primary keys, which are values that instances of entity components
Department of IT, JCET, Trichy. Page 15

Attributes and configuration
Home interfaces
15. What is facet
A special of CCM components is the equivalent interface, which enables
navigation between the different facts of a CCM component.
16. What is Receptacles
Receptacles provide connect and disconnect operations and internally
correspond
to object references top other objects of appropriate type.
17. What is home interface
The home interface is provided by a component, not its instances, and supports
the
creation of new instances.
18. What is the use of primary keys
Primary keys which are values that instances of entity components provide to
allow client identification of the instances.
19. What is attribute and configuration
Configuration interfaces support initial configuration of new component instances.
They are described as IDL attributes with set and get operations.
20. What is MDA
The OMG architecture board introduced a new approach called model driven
architecture for all forthcoming OMG specifications.
Department of IT, JCET, Trichy. Page 16

UNIT IV
BIG QUESTIONS:
1. Explain briefly about the CORBA services
Services supporting enterprise distributed computing.
Services supporting architecture using fine-grained objects.
2. Explain the CORBA component model.
Portable object adapter
CCM components
CCM containers
3. Write short notes on SOM and MDA.
SOM
Meta programming
Binary compatibility
MDA
4. Explain briefly about IDL interface.
_ IDL interface
_ Modules
_ Data types
5. Explain briefly about CCM components.
_ Features
_ Diagram
Department of IT, JCET, Trichy. Page 17

UNIT-V
1. Define COM
COM is binary standard, it specifies nothing about how a particular programming
language may be bound to it. COM does not specify what a component or an
object is.
2. Draw the binary representation of a COM interface.
Client variable
3. Name and two interfaces that is used in COM
Query interface
Iunknown interface
4. What is the use of Query interface method
Query interface takes the name of an interface, checks if the current COM object
supports it, and if so returns the corresponding interface reference.
5. What is the use of Iunknown interface
The identity of the Iunknown interface can serve to identify the entire COM object
with out requiring any specific functionality.
6. What are the methods supported by Iunknown interface
Query Interface
AddRef
AddRelease
7.Specify the use of HRESULT type.
The type HRESULT is used by most COM interface methods to indicate
success or failure to call. It may also indicate network failure.
Interface node
OP1
OP2
OPn
Component
Department of IT, JCET, Trichy. Page 18

8. What is AddRef and Release
On creation of an object or node, the reference count is initialized to 1
before handling out a first reference. Each time a copy of a reference is created
the count must be incremented (AddRef). Each time a reference is given up, the
count must be decremented (Release).
9. Specify the two forms of object reuse.
Containment
Aggregation
10. What is containment
Containment is a form of object reuse. It is just the simple object composition
technique. One object holds an exclusive reference to another. Here the call is
forwarded
and handled by another object.
11. What is aggregation
Aggregation is a form of object reuse. Here instead of forwarding requests, an
inner object’s interface reference could be handed out directly to another object’s
client.
12. When we use Aggregation
Aggregation is only useful where the outer object does not wish to intercept calls
to perform some filtering or additional processing.
13. Compare COM and DCOM.
DCOM transparently expands the concepts and services of COM. DCOM builds
on the client-side proxy objects and the server side stub objects already present
in COM.
14. What is outgoing interface
An outgoing interface is an interface that a COM object would use if it were
“connected” to an object that provides this interface.
15. Name the interface that is declared within outgoing interface.
IConnectionPointContainer
IConectionPoint
Department of IT, JCET, Trichy. Page 19

16. Specify the use of IConnectionPointContainer
Using IConnectionPointContainer ,the various connection point objects of a
connectable object can be found and enumerated.
17. Specify the use ofIConnectionPoint
IConnectionPoint can be used to establish, enumerate and tear down
connections.
18. How the connectable objects implement change propagation
Connectable objects provide a uniform way to implement change propagation. As
outgoing and incoming interfaces are matched, the propagation can take the
form of
regular method invocations instead of requiring the creation of event objects.
19. Specify the policies that are used to determine the shared assemblies in
GAC.
Publisher policy
Application policy
Machine policy
20. What is Appdomains
The CLR execution engine partitions a process into one or more AppDomains.
An
AppDomain isolates sets of object from all objects in other appdomain, but is
more light weight and cheaper than operating systems.
21. What are contexts
A context is a partition of an appdomain the member objects, objects of which
share the propreties of their contexts.
22. What is reflection
The CLI reflection support grants full access to the type structure of loaded
assemblies including all attributes defined on these types.
23. What is remoting
The CLI remoting support combines context and reflection infrastructure with
flexible support for proxies, channels and messages provide building blocks for a
wide variety of communication styles and patterns.
Department of IT, JCET, Trichy. Page 20

UNIT V
BIG QUESTIONS:
1. Explain the COM services in detail.
Dispatch interfaces
Connectable objects
2. Explain in detail the compound document and OLE.
OLE containers and services
Controls-ActiveXcontrols
3. Explain briefly about the .Net components.
Assemblies
Single application
Shared application
Policies
4. Write short notes on AppDomains, contexts, reflection,remoting
AppDomains
o Loading
o Unloading
Contexts
o Context bound
o Context Agile
Reflection
Remoting
5. Explain about dual interface and outgoing interfaces.
o Dual interface
_ Idispatch method
_ DispID
o Outgoing interface
_ IConnectionPointContainer
_ IConnectionPoint
Department of IT, JCET, Trichy. Page 21