Multiple
Choice Questions
1 1. What dose the Java compiler translate the java
program into?
a. Byte Code b. Hill
c. Code d. Source Code
2 2. Command javac is used for?
a. Interpretation b.
Compilation
c. Running d.
Execution
3 3. Which one of the following is used to create a
new class based on an existing class?
a.
Polymorphism b.
Inheritance
c. Encapsulation d. Class
4 4. What is the extension of saved Java file ?
a.
.java b. .doc
c. .png d.
.jpeg
5 5. Which one of the following is used to create a
new class based on an existing class?
a. Class b.
Data Abstraction
c. Encapsulation d. Polymorphism
Fill in the
Blanks :-
11. Java is an example of oops programming.
22. An object is an instance of class.
33. The objects
interact with each other by sending messages.
44. The main()
method shows from where the program will start running.
55. The existing class in inheritance is known as base class
Subjective Qustions :-
Qus.: List of Advantages of OOPs.
Ans:
(1) Elimination of
redundant coding system and usage of existing classes through inheritance.
(2) Program can be
developed by sharing existing modules.
(3) Possibilities of
multiple instance of an objects without any interference.
(4) Security of data
values from other segment of the program through data hiding.
Qus.
– Distinguish between data abstraction and data encapsulation.
BASIS FOR
COMPARISON
|
ABSTRACTION
|
ENCAPSULATION
|
Basic
|
Shows, what elements are necessary to build a system.
|
Hides the complexity of a system.
|
Application
|
During 'design level'.
|
During 'Implementation level'.
|
Focus-1
|
Focus is on "what" should be done
|
Focus is on "how" it should be done.
|
Achieved
|
Achieved through encapsulation.
|
Achieved through making the members of a class as 'private'.
|
Focus-2
|
Implementation hiding.
|
Information hiding.
|
Example
|
The GUI of a mobile phone, it has some icons to click on,
which on click perform the specific function.
|
After the icon is clicked, the end user has no idea regarding
its implementation details
|
Qus.- What is JRE.
Ans.
:- JRE stands for “Java Runtime Environment”. It consists of
all the programs and files required to run application in the Java programming
language. The Software JRE consists of JVM(Java Virtual Machine) and the Java
class libraries.
Qus.-
Describe the feature of the Java
programming language ?
Ans.
:- Basic
features of Java programming language as follows:
i) It is an object oriented language.
ii) Java program is both compiled and interpreted.
iii) Java program can be application or applet.
iv) Java is case sensitive language, i.e. it distinguished upper and lower case letters.
i) It is an object oriented language.
ii) Java program is both compiled and interpreted.
iii) Java program can be application or applet.
iv) Java is case sensitive language, i.e. it distinguished upper and lower case letters.
Qus.- What is the main() method of Java ?
Ans.
:- main() is the method of java from where a program execution begins. This
method is called when we execute the program. In the main method, we can create
an object of the defined class and have an access to the member method by using
the dot(.) operator. The beginning and ending of the main method is done by
using‘{‘ and ‘}’respectively.
Lab Question :
Qus. : Write a program to print ‘life is
awesome’.
Solution :-
class
Print
{
public static void main(String
args[])
{
System.out.println(“life is awesome”);
}
}
Qus. : Identify the output of the following
program.
class
Lab
{
public static void main(String[] args)
{
System.out.println(“Hello
how do you do”);
}
}
Solution :-
output :- Hello how do you
do
Qus. – Identify the errors in the given program :
- class Demo
- {
- main(String[] args)
- {
- System.println(“all izz well”)
- }
- }
Solution :
-
At
line number 3 “public static void” is missing before main word.
-
At
line number 5 “out” is missing after System word.
-
At
line number 5 “;” is missing at the end of the line.
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