Interview Questions Answers in Core Java, Design Patterns, C

why the constructor should be used in class,if there is no
constructor what will happen?

Answer

Hi... Nothing will happen the compilet will supply the
default constructor of the class.Normally canostructor can
be used to instantiate an object.

Is This Answer Correct ?

1 Yes

0 No

Question { 8897 }

what is java

Answer

Hi...
JAVA is an object-oriented programming language.It support
sophisticated OOP'S concepts
like "Encapsulation", "Polymorphism" and "Inheritance".By
using java we can develop web-based applications,client-
server applications and distributed applications. Java is a
most suitable programming language for internet
technologies.The Sun's trade mark slogan is "WRITE ONECE
RUN ANYWARE", till now no programming is not achieving this
slogan, it is a platform independent and both compielet and
interpreted langauage.

Is This Answer Correct ?

0 Yes

0 No

Question { TCS, 15492 }

When does the compiler supply a default constructor for a
class?

Answer

Hi... The compiler will supply defaulst constructor when u
not supplied constructor in the program.

Is This Answer Correct ?

5 Yes

2 No

Question { Accenture, 8434 }

Which Math method is used to calculate the absolute value of
a number?

Answer

Hi...
You can use Math.abs(); method .This is static method
defined in the Math class.

Is This Answer Correct ?

16 Yes

1 No

Question { 9526 }

What is more advisable to create a thread, by implementing
a Runnable interface or by extending Thread class?

Answer

Hi...To create a Thread ,implement the Runnable interface
it is more advisable than extending a Thread class.By
extending the Thread class u can't achieve the multiple
inheritance.So implementing the Runnable interface is good
programming practice.

public class ThreadTest extends Thread,Applet
//This is illegal

public class ThreadTest extends Applet implements Runnable
//This is legal.

Is This Answer Correct ?

3 Yes

0 No

Question { Honeywell, 9070 }

what is MVC Pattern?

Answer

Hi... MVC is the one of the design pattern which enables
you to de-coupling the modules.
MODEL:It cane be used to store the database objects.
VIEW: It can be used to view purpose,to giving the user
input.
CONTROLLER:It is the main component in the MVC
pattern,which can handle request and response mechanism.

Is This Answer Correct ?

6 Yes

2 No

Question { Honeywell, 13979 }

Which Design Patterns you know?

Answer

Hi... For this question u can answer like Singleton design
pattern ,DAO and DTO,MVC.

Is This Answer Correct ?

2 Yes

1 No

Question { Honeywell, 9884 }

What are actually Model,view,Controller in MVC Pattern?

Answer

Hi...
MODEL:Model is nothing but storing the databse objects.
VIEW: View is nothing but userinterface
CONTROLLER: Controller is nothing but handling the requests
and sending the response.

Is This Answer Correct ?

5 Yes

3 No

Question { Honeywell, 9439 }

If there is a Model class,View class,Controller class then
How these are internally related? Which layer objects
instantiated in which layer? How they communicates?

Answer

Hi... Model is nothing but a class/bean having the setters
and getters methods to providing the required information
to the controller(SERVLET) and View(JSP).First the client
will give the request by using the view(jsp),the view can
forward the data to controller(servlet)then the controler
process the request based on the Model components .Finally
the servlet send the response to view.

Is This Answer Correct ?

3 Yes

2 No

Question { Honeywell, 15879 }

what is data access layer?

Answer

Hi... Data access layer is nothing but EIS(Enterprise
Information Server)which can store the databse objects
associated to the webapplication.

Is This Answer Correct ?

1 Yes

2 No

Question { Covansys, 7814 }

what is the difference b/w design pattern and architecture

Answer

Hi...
Architecture is nothing but plan for a specfic problem.
Design pattern is a solution for a given problem.I think in
java perspective "class" is a plan(blue print) and "object"
is a solution.

Is This Answer Correct ?

1 Yes

7 No

Question { CTS, 47317 }

who was the founder of java

Answer

Hi,
"James Gosling" is the founder of java.

Is This Answer Correct ?

236 Yes

8 No

Question { BMC, 7694 }

What is encapsulation? Elaborate with example?

Answer

Hi,
Encapsulation: The wrapping up of a data and methods into a
single unit is called Encapsulation. You can achieve
Encapsulation by using private data and public methods look
at the following example for better understanding.
Eg:
public class EcapTest{
public static void main(String args[]){
private int a=22;
private String s="DEVARATHNAM";
private float f=33.24f;

public void displayData(){
// some code
}
public void getData(){
// some code
}
}//main
{//class.

Observe the above program we are combining both data and
methods into a single unit(EcapTest). I hope i met your
needs.

Is This Answer Correct ?

23 Yes

5 No

Question { 6357 }

How GC (Garbage Collector) knows the objects reference is
unused.Whether GC removes the unused object Parmanently or
it maintains something.

Answer

Hi,
The Garbage Collector(GC)will be always under the control
of JVM, So JVM periodically runs the GC. It uses "sweep"
and "mark" algorithms to identify the unused objects in the
application. You don't bother about GC, JVM will take of it.

Is This Answer Correct ?

9 Yes

0 No

Question { Solartis, 55389 }

52.write a “Hello World” program in “c” without using a
semicolon?
53.Give a method to count the number of ones in a 32 bit number?
54.write a program that print itself even if the source file
is deleted?
55.Given an unsigned integer, find if the number is power of 2?

Answer

Hi Sujatha,

Program for your question no.52.

#include
main()
{
if(Printf("Hello World!!!"))
}
Here I didn't use semicolon, I hope I met your criteria.

Is This Answer Correct ?

267 Yes

137 No

devarathnam c,kotagudiban