Download CUSTOMER_CODE SMUDE DIVISION_CODE SMUDE

CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
APR2016
ASSESSMENT_CODE BT0074_APR2016
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
4826
QUESTION_TEXT
Explain Inner classes and anonymous classes
SCHEME OF EVALUATION
Inner classes - description + syntax= 2.5 + 2.5 = 5 Marks
Anonymous classes - description + example=2.5+2.5= 5 Marks
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73246
QUESTION_TEXT
How relationships are classified in Java? Explain.
SCHEME OF
EVALUATION
The types of relationships are:
● A Kind Of relationship
● A Is-A relationship
● A Part-Of-relationship
● A Has-A relationship
(For classifying 2 marks)
(Each classification’s explanation with example – 2 marks
each)
QUESTION_TYPE DESCRIPTIVE_QUESTION
QUESTION_ID
73249
QUESTION_TEXT Define Servlet. Describe the Servlet Life Cycle.
SCHEME OF
EVALUATION
A servlet is a small pluggable extension to a server that enhances the
server’s functionality.
(1 mark)
Servlet Life Cycle:
It has 9 stages. They are:
1. The server loads the servlet when it is first requested by the client or
if configured to do so, at server start-up. The servlet may be loaded from
either a local or a remote location using the standard Java class loading
facility.
This step is equivalent to the following code:
Class c=Class.forName(“com.sourcestream.MyServlet”);
It should be noted that when referring to servlets, the term load often
refers to the process of both loading and instantiating the servlet.
2. The server creates one or more instances of the servlet class.
Depending on implementation the server may create a single instance that
services all requests through multiple threads or create a pool of instances
from which one chosen to service at each new request. This step is
equivalent to the following Java code:
Servlet s=(Servlet) c.newInstance(); where ‘c’ is the same Class object
created in previous step.
3. The server constructs a ServerConfig object that provides
initialization information to the servlet.
4. The server calls the servlet’s init() method, passing the object
constructed in step 3 as a parameter. The init() method is guaranteed to
finish execution prior to the servlet processing the first request. If the
server has created multiple servlet instances (step 2), the init() method is
called one time for each instance.
5. The server constructs a ServletRequest or HttpServletRequest object
from the data included in the client’s request. It also constructs a
ServletResponse or HttpServletResponse object that provides methods for
customizing the server’s response. The type of object passed in these two
parameters depends on whether the servlet extends the GenericServlet
class or the HttpServlet class, respectively.
6. The server calls the servlet’s service() method passing the objects
constructed in step 5 as parameters. When concurrent requests arrive,
multiple service() methods can run in separate threads.
7. The service() method processes the client request by evaluating the
ServletRequest or HttpServletRequest object and responds using
ServletResponse or HttpServletResponse object.
8. If the server receives another request for this servlet, the process
begins again at step 5.
9. When instructed to unload the servlet, perhaps by the server
administrator or programmatically by the servlet itself, the server calls the
servlet’s destroy() method. The servlet is then eligible for garbage
collection.
(Each step – 1 mark)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
115104
QUESTION_TEXT
Explain the different methods of Input stream class.
1.
SCHEME OF EVALUATION 2.
3.
int read ( )
int read (byte [ ] b)
int read (byte [ ] b, int off, int len)
4.
int available ( )
5.
void close( ) – Explain briefly 2 × 5 = 10 marks)
QUESTION_T
DESCRIPTIVE_QUESTION
YPE
QUESTION_ID 115106
QUESTION_T Give a detailed description of Remote Method Invocation mechanism in
EXT
JAVA.
RMI is built upon the specification of how local and remote objects
interoperate. Local objects are objects that execute on the local machine.
Remote objects are objects that execute on all the other machines. Objects on
remote hosts are exported so that they can be invoked remotely. An object
exports itself by registering itself with a Remote Registry
Server.
2marks
A Remote Registry Server is a service that runs on a server and helps the
objects on other hosts to remotely access its registered objects. The registry
service maintains a database of all the named remote
objects.
1mark
SCHEME OF
EVALUATION
3marks
A Distributed Application Created Using RMI;
Objects that are exported for remote access must implement the interface
RemoteInterface. This interface identifies the object to be accessed remotely.
All the methods that are to be invoked remotely must throw a
RemoteException. This exception is used to handle the errors that may occur
during the invocation of a remote method.
2marks
Java's RMI approach is organized into a client/server framework. A local
object that invokes a method of a remote object is referred to as a client
object, and the remote object whose methods are invoked is referred to as a
server object.
1mark
Java's RMI approach makes use of stubs and skeletons. A stub is a local
object on the client's machine that acts as a proxy for a remote object.RMI
uses the TCP protocol for transporting information.
1mark
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
115107
QUESTION_TEXT
What is Java IDL?
*
It is a technology for distributed object that us objects interacting
on different platforms across a network.
*
It is similar to RMI, Which supports distributed objects written
entirely in the java programming language. It also enables objects to
interact regardless of whether they are written in the java programming
language or another language such as C,C++,COBOL.
SCHEME OF
EVALUATION
*
It is based on the common object request brokerage architecture,
an industry –standard distributed object model.
*
A key feature of CORBA is IDL, a language-neutral interface
definition language. Java IDL supports mapping for java.
*
To support interaction between objects in separate programs, Java
IDL provides an object Request Broker, or ORB. The ORB is a class
library that enables low level communication between java IDL
applications and other CORBA-compliant applications.
(2 marks each)