CORE JAVA MCQs with Answer
1. What is the
range of short data type in Java?
a) -128 to 127
b) -32768 to 32767
c) -2147483648
to 2147483647
d) -5000 TO 5000
2. What is the
range of byte data type in Java?
a) -128 to 127
b) -32768 to
32767
c) -2147483648
to 2147483647
d) -5000 TO 5000
3. An expression
involving byte, int, and literal numbers is promoted to which of these?
a) int
b) long
c) byte
d) float
4. Which of
these literals can be contained in float data type variable?
a) -1.7e+308
b) -3.4e+038
c) +1.7e+308
d) -3.4e+050
5. Which data
type value is returned by all transcendental math functions?
a) int
b) float
c) double
d)long
6. What will be
the output of the following Java code?
class increment {
public static void main(String args[])
{
int g = 3;
System.out.print(++g * 8);
}
}
a) 25
b) 24
c) 32
d) 33
7. What is the
numerical range of a char data type in Java?
a) -128 to 127
b) 0 to 256
c) 0 to 32767
d) 0 to 65535
8. Which of
these coding types is used for data type characters in Java?
a) ASCII
b) ISO-LATIN-1
c) UNICODE
d) CODE
9. Which of
these values can a boolean variable contain?
a) True & False
b) 0 & 1
c) Any integer
value
d) true
10. Which of
these occupy first 0 to 127 in Unicode character set used for characters in
Java?
a) ASCII
b) ISO-LATIN-1
c) LATIN1
d) ASCII and ISO-LATIN1
11. Which one is
a valid declaration of a boolean?
a) boolean b1 =
1;
b) boolean b2 =
‘false’;
c) boolean b3 = false;
d) boolean b4 =
‘true’
12. What will be
the output of the following Java code?
class booloperators {
public static void main(String args[])
{
boolean var1 = true;
boolean var2 = false;
System.out.println((var1 &
var2));
}
}
a) 0
b) 1
c) true
d) false
13. Which of
these is long data type literal?
a) 0x99fffL
b) ABCDEFG
c) 0x99fffa
d) 99671246
14. Which of
these can be returned by the operator &?
a) Integer
b) Boolean
c) Character
d) Integer or Boolean
15. Literals in
java must be appended by which of these?
a) L
b) l
c) D
d) L and I
16. Which of
these can not be used for a variable name in Java?
a) identifier
b) keyword
c) identifier
& keyword
d) constant
17. How is Date
stored in database?
a) java.sql.Date
b)
java.util.Date
c)
java.sql.DateTime
d) java.util.DateTime
18. What does
LocalTime represent?
a) Date without
time
b) Time without Date
c) Date and Time
d) Date and Time
with timezone
19. What will be
the output of the following Java program?
class c
{
public void main( String[] args )
{
System.out.println(
"Hello" + args[0] );
}
}
a) Hello c
b) Hello
c) Hello world
d) Runtime Error
20.Which
of these operators is used to allocate memory to array variable in Java?
a) malloc
b) alloc
c) new
d) new malloc
21. Which of
these is an incorrect array declaration?
a) int arr[] =
new int[5]
b) int [] arr =
new int[5]
c) int arr[] =
new int[5]
d) int arr[] = int [5] new
22. What will be
the output of the following Java code?
int arr[] = new int [5];
System.out.print(arr);
a) 0
b) value stored
in arr[0]
c) 00000
d) Class name@ hashcode in hexadecimal form
23. Which of
these is an incorrect Statement?
a) It is necessary to use new operator to initialize
an array
b) Array can be
initialized using comma separated expressions surrounded by curly braces
c) Array can be
initialized when they are declared
d) Array used
curly braces
24. Which of
these is necessary to specify at time of array initialization?
a) Row
b) Column
c) Both Row and
Column
d) Table
25. What will be
the output of the following Java code?
class evaluate
{
public static void main(String args[])
{
int arr[] = new int[] {0 , 1, 2,
3, 4, 5, 6, 7, 8, 9};
int n = 6;
n = arr[arr[n] / 2];
System.out.println(arr[n] / 2);
}
}
a) 3
b) 0
c) 6
d) 1
26. Which of the
following can be operands of arithmetic operators?
a) Numeric
b) Boolean
c) Characters
d) Numeric & Characters
27. Modulus
operator, %, can be applied to which of these?
a) Integers
b) Floating –
point numbers
c) Integers and
floating – point numbers
d) point numbers
28.With x = 0,
which of the following are legal lines of Java code for changing the value of x
to 1?
1. x++;
2. x = x + 1;
3. x += 1;
4. x =+ 1;
a) 1, 2 & 3
b) 1 & 4
c) 1, 2, 3 & 4
d) 3 & 2
29. Decrement
operator, −−, decreases the value of variable by what number?
a) 1
b) 2
c) 3
d) 4
30.What will be
the output of the following Java program?
class increment
{
public static void main(String args[])
{
int g = 3;
System.out.print(++g * 8);
}
}
a) 25
b) 24
c) 32
d) 33
31. Which of
these is not a bitwise operator?
a) &
b) &=
c) |=
d) <=
32. Which
operator is used to invert all the digits in a binary representation of a
number?
a) ~
b) <<<
c) >>>
d) ^
33. On applying
Left shift operator, <<, on integer bits are lost one they are shifted
past which position bit?
a) 1
b) 32
c) 33
d) 31
34. Which right
shift operator preserves the sign of the value?
a) <<
b) >>
c) <<=
d) >>=
35.What is the
output of relational operators?
a) Integer
b) Boolean
c) Characters
d) Double
36. Which of
these is returned by “greater than”, “less than” and “equal to” operators?
a) Integers
b) Floating –
point numbers
c) Boolean
d) Character
37. Which of
these operators can skip evaluating right hand operand?
a) !
b) |
c) &
d) &&
38. Which of
these statements is correct?
a) true and
false are numeric values 1 and 0
b) true and
false are numeric values 0 and 1
c) true is any
non zero value and false is 0
d) true and false are non numeric values
39.Which of
these have highest precedence?
a) ()
b) ++
c) *
d) >>
40. What is the
value stored in x in the following lines of Java code?
int x, y, z;
x = 0;
y = 1;
x = y = z = 8;
a) 0
b) 1
c) 9
d) 8
41. What is the
value stored in x in the following lines of Java code?
int x, y, z;
x = 0;
y = 1;
x = y = z = 8;
a) 0
b) 1
c) 9
d) 8
42. Which of
these keywords is used to define packages in Java?
a) pkg
b) Pkg
c) package
d) Package
43. Which of
these is a mechanism for naming and visibility control of a class and its
content?
a) Object
b) Packages
c) Interfaces
d) None of the
Mentioned.
44. Which of
these access specifiers can be used for a class so that its members can be
accessed by a different class in the different package?
a) Public
b) Protected
c) Private
d) Friendly
45. Which of the
following is the correct way of importing an entire package ‘pkg’?
a) import pkg.
b) Import pkg.
c) import pkg.*
d) Import pkg.*
46. Which of the
following is an incorrect statement about packages?
a) Package defines
a namespace in which classes are stored
b) A package can
contain other package within it
c) Java uses
file system directories to store packages
d) A package can be renamed without renaming the
directory in which the classes are stored
47. Which of
these selection statements test only for equality?
a) if
b) switch
c) if &
switch
d) if-else
48. Which of
these are selection statements in Java?
a) if()
b) for()
c) continue
d) break
49. Which of the
following loops will execute the body of loop even when condition controlling
the loop is initially false?
a) do-while
b) while
c) for
d) for-each
50. Which of
these jump statements can skip processing the remainder of the code in its body
for a particular iteration?
a) break
b) return
c) exit
d) continue
51. Which of
this statement is incorrect?
a) switch
statement is more efficient than a set of nested ifs
b) two case constants in the same switch can have
identical values
c) switch
statement can only test for equality, whereas if statement can evaluate any
type of boolean expression
d) it is
possible to create a nested switch statements
52. What is the
output of Java program with IF statement?
if(1)
{
System.out.println("OK");
}
A) OK
B) No output
C) Compiler
error
D) Runtime error
53. If the condition of an IF-statement is false,
which is true below.
A) IF block is executed.
B) ELSE block
is executed.
C) Both IF and ELSE blocks are skipped.
D) Both IF and ELSE blocks are executed.
54. An ELSE
statement must be preceded by ___ statement in Java.
A) IF
B) ELSE IF
C) IF or ELSE IF
D) IF ELSE
55. An IF
statement in Java is also a ___ statement.
A) boolean
B) conditional
C) iterative
D) optional
56. An IF or
ELSE IF statement accepts ___ as input before branching.
A) boolean
B) int
C) float
D) char
57. Which of the
following is not OOPS concept in Java?
a) Inheritance
b) Encapsulation
c) Polymorphism
d) Compilation
58. Which of the
following is a type of polymorphism in Java?
a) Compile time polymorphism
b) Execution
time polymorphism
c) Multiple
polymorphism
d) Multilevel
polymorphism
59. When does
method overloading is determined?
a) At run time
b) At compile time
c) At coding
time
d) At execution
time
60. Which of
these keywords is used to make a class?
a) class
b) struct
c) int
d) none of the
mentioned
61. Which of the
following is a valid declaration of an object of class Box?
a) Box obj = new Box();
b) Box obj = new
Box;
c) obj = new
Box();
d) new Box obj;
62. Which of
these operators is used to allocate memory for an object?
a) malloc
b) alloc
c) new
d) give
63. What is the
process of defining more than one method in a class differentiated by method
signature?
a) Function
overriding
b) Function overloading
c) Function
doubling
d) None of the
mentioned
64. Which of the
following is a method having same name as that of it’s class?
a) finalize
b) delete
c) class
d) constructor
65. Which method
can be defined only once in a program?
a) main method
b) finalize
method
c) static method
d) private
method
66. Which of
these class is superclass of String and StringBuffer class?
a) java.util
b) java.lang
c) java.sql
d) java.io
67. Which of
these operators can be used to concatenate two or more String objects?
a) +
b) +=
c) &
d) ||
68. Which of
this method of class String is used to obtain a length of String object?
a) get()
b) Sizeof()
c) lengthof()
d) length()
69. Which of
these method of class String is used to extract a single character from a
String object?
a) CHARAT()
b) chatat()
c) charAt()
d) ChatAt()
70. Which of
these constructors is used to create an empty String object?
a) String()
b) String(void)
c) String(0)
d) String
71. Which of
these is correct way of inheriting class A by class B?
a) class B +
class A {}
b) class B
inherits class A {}
c) class B extends A {}
d) class B
extends class A {}
72. What is not
type of inheritance?
a) Single
inheritance
b) Double inheritance
c) Hierarchical
inheritance
d) Multiple
inheritance
73. Using which
of the following, multiple inheritance in Java can be implemented?
a) Interfaces
b)
Multithreading
c) Protected
methods
d) Private
methods
74. All classes
in Java are inherited from which class?
a)
java.lang.class
b)
java.class.inherited
c)
java.class.object
d) java.lang.Object
75. In order to
restrict a variable of a class from inheriting to subclass, how variable should
be declared?
a) Protected
b) Private
c) Public
d) Static
76. From the following statements which is a disadvantage of an java array?
class Subclass-name extends Superclass-name
{
//methods and fields
}
1. int a[]=new int[5];
2. a[10]=50;
it would result in ______.
class Simple{
public static void main(String args[]){
String s="sunita";
System.out.println(s.length());//6
}
}
class Modulus {
public static void main(String args[]) {
int x = 42;
double y = 42.25;
System.out.println("x mod 10 = " + x % 10);
System.out.println("y mod 10 = " + y % 10);
}
}
y mod 10 = 2.25
y mod 10 = 2.50
y mod 10 = 3.25
y mod 10 = 4.25
1. When does Exceptions in Java arises in code sequence?
a) Run Time
b) Compilation
Time
c) Can Occur Any
Time
d) None of the
mentioned
2. Which of
these keywords is not a part of exception handling?
a) try
b) finally
c) thrown
d) catch
3. Which of
these keywords must be used to monitor for exceptions?
a) try
b) finally
c) throw
d) catch
4. Which of
these keywords must be used to handle the exception thrown by try block in some
rational manner?
a) try
b) finally
c) throw
d) catch
5. Which of
these keywords is used to manually throw an exception?
a) try
b) finally
c) throw
d) catch
6. What requires
less resources?
a) Thread
b) Process
c) Thread and
Process
d) Neither
Thread nor Process
7. What does not
prevent JVM from terminating?
a) Process
b) Daemon Thread
c) User Thread
d) JVM Thread
8. What decides
thread priority?
a) Process
b) Process
scheduler
c) Thread
d) Thread scheduler
9. What is true
about time slicing?
a) Time slicing
is OS service that allocates CPU time to available runnable thread
b) Time slicing is the process to divide the available
CPU time to available runnable thread
c) Time slicing
depends on its implementation in OS
d) Time slicing
allocates more resources to thread
10. What should
not be done to avoid deadlock?
a) Avoid using
multiple threads
b) Avoid hold
several locks at once
c) Execute foreign code while holding a lock
d) Use
interruptible locks
11. What is true
about threading?
a) run() method
calls start() method and runs the code
b) run() method
creates new thread
c) run() method
can be called directly without start() method being called
d) start() method creates new thread and calls code
written in run() method
12. Which of the
following is a correct constructor for thread?
a) Thread(Runnable a, String str)
b) Thread(int
priority)
c)
Thread(Runnable a, int priority)
d)
Thread(Runnable a, ThreadGroup t)
13. Which of the
following stops execution of a thread?
a) Calling
SetPriority() method on a Thread object
b) Calling notify() method on an object
c) Calling
wait() method on an object
d) Calling
read() method on an InputStream object
14. Which of the
following will ensure the thread will be in running state?
a) yield()
b) notify()
c) wait()
d)
Thread.killThread()
15. Which of
these stream contains the classes which can work on character stream?
a) InputStream
b) OutputStream
c) Character Stream
d) All of the
mentioned
16. Which of
these class is used to read characters in a file?
a) FileReader
b) FileWriter
c)
FileInputStream
d)
InputStreamReader
17. Which of
these method of FileReader class is used to read characters from a file?
a) read()
b) scanf()
c) get()
d) getInteger()
18. Which of these
class can be used to implement the input stream that uses a character array as
the source?
a)
BufferedReader
b) FileReader
c) CharArrayReader
d)
FileArrayReader
19. Which of
these classes can return more than one character to be returned to input stream?
a)
BufferedReader
b)
Bufferedwriter
c) PushbachReader
d)
CharArrayReader
20. Which of
these package contains classes and interfaces for networking?
a) java.io
b) java.util
c) java.net
d) java.network
21. Which of
these is a protocol for breaking and sending packets to an address across a
network?
a) TCP/IP
b) DNS
c) Socket
d) Proxy Server
22. How many
ports of TCP/IP are reserved for specific protocols?
a) 10
b) 1024
c) 2048
d) 512
23. How many
bits are in a single IP address?
a) 8
b) 16
c) 32
d) 64
24. Which of
these is a full form of DNS?
a) Data Network
Service
b) Data Name
Service
c) Domain
Network Service
d) Domain Name Service
25. Which of
these class is used to encapsulate IP address and DNS?
a)
DatagramPacket
b) URL
c) InetAddress
d) ContentHandler
26. Unchecked exceptions are checked at compile-time rather they are checked at runtime.
class Student{
int id;
String name;
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student s1=new Student();
Student s2=new Student();
s1.display();
s2.display();
}
}
By extending Thread class
By implementing Runnable interface.
are used to?
NullPointerException,
ArrayIndexOutOfBoundsException,
ArithmeticException,
NumberFormatException
are seen in _______
1. Which of
these packages contains all the classes and methods required for even handling
in Java?
a) java.applet
b) java.awt
c) java.event
d) java.awt.event
2. What is an
event in delegation event model used by Java programming language?
a) An event is an object that describes a state change
in a source
b) An event is
an object that describes a state change in processing
c) An event is
an object that describes any change by the user and system
d) An event is a
class used for defining object, to create events
3. Which of
these methods are used to register a keyboard event listener?
a) KeyListener()
b) addKistener()
c) addKeyListener()
d)
eventKeyboardListener()
4. Which of
these methods are used to register a mouse motion listener?
a) addMouse()
b)
addMouseListener()
c) addMouseMotionListner()
d)
eventMouseMotionListener()
5. What is a
listener in context to event handling?
a) A listener is
a variable that is notified when an event occurs
b) A listener is a object that is notified when an
event occurs
c) A listener is
a method that is notified when an event occurs
d) None of the
mentioned
6. Event class
is defined in which of these libraries?
a) java.io
b) java.lang
c) java.net
d) java.util
7. Which of these
methods can be used to determine the type of event?
a) getID()
b) getSource()
c) getEvent()
d)
getEventObject()
8. Which of
these class is super class of all the events?
a) EventObject
b) EventClass
c) ActionEvent
d) ItemEvent
9. Which of
these events will be notified if scroll bar is manipulated?
a) ActionEvent
b)
ComponentEvent
c) AdjustmentEvent
d) WindowEvent
10. Which of
these events will be generated if we close an applet’s window?
a) ActionEvent
b)
ComponentEvent
c)
AdjustmentEvent
d) WindowEvent
11. Which of
these packages contains all the event handling interfaces?
a) java.lang
b) java.awt
c) java.awt.event
d) java.event
12. Which of
these interfaces handles the event when a component is added to a container?
a)
ComponentListener
b) ContainerListener
c) FocusListener
d) InputListener
13. Which of
these interfaces define a method actionPerformed()?
a)
ComponentListener
b)
ContainerListener
c) ActionListener
d) InputListener
14. Which of
these interfaces define four methods?
a) ComponentListener
b)
ContainerListener
c)
ActionListener
d) InputListener
15. Which of
these interfaces define a method itemStateChanged()?
a)
ComponentListener
b)
ContainerListener
c)
ActionListener
d) ItemListener
17. Which of
these methods will be invoked if a character is entered?
a) keyPressed()
b) keyReleased()
c) keyTyped()
d) keyEntered()
18. Which of
these methods is defined in MouseMotionAdapter class?
a) mouseDragged()
b)
mousePressed()
c)
mouseReleased()
d)
mouseClicked()
19. Which of
these is a superclass of all Adapter classes?
a) Applet
b)
ComponentEvent
c) Event
d) InputEvent
20. Which of the
following class is derived from the container class?
a)
Component
b) Panel
c) MenuComponent
d) List
a)Window
b)Panel
c)Dialog
d)Frame
22.Which
abstract class is the super class of all menu related classes?
a) MenuComponent
b )MenuBar
c )MenuItem
d) CheckboxMenuItem
23. Which of the
following is the default Layout Manager ?
a) FlowLayout
b) BorderLayout
c)GridLayout
d)CardLayout
24. How do you
change the current layout manager for container?
A. use
setLayout()
B. once created you cannot change it
C. You set setLayoutManager()
D. use updateLayout()
25. AWT
components are
A) lightweight
B) heavyweight
C) equalweight
D) weightless
26. Which of
these packages contain all the collection classes?
a) java.lang
b) java.util
c) java.net
d) java.awt
27. Which of
these classes is not part of Java’s collection framework?
a) Maps
b) Array
c) Stack
d) Queue
28. Which of
this interface is not a part of Java’s collection framework?
a) List
b) Set
c) SortedMap
d) SortedList
29. Which of
these methods deletes all the elements from invoking collection?
a) clear()
b) reset()
c) delete()
d) refresh()
30. What is
Collection in Java?
a) A group of objects
b) A group of
classes
c) A group of
interfaces
d) A group of
array
No comments: