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SCJP 1.4 Mock Exam – 9


1.What is the result when you compile and run the
following code?

class Top
{


static void myTop() {


System.out.println(“Testing myTop method
in Top class”);


}

}


public class Down extends Top {


void myTop() {

System.out.println(“Testing myTop method in Down
class”);


}


public static void main(String [] args)
{


Top t = new
Down();

t.myTop();


}

}

A) Compile
Time error

B)
Runtime error

C)
Prints Testing myTop method in Top class on the
console

D)
Prints Testing myTop method in Down class on the
screen


2. Which of the code fragments will throw an
“ArrayOutOfBoundsException” ?

A) for (int
i = 0; i < args.length; i ++ ) {

System.out.print( i ) ;


}

B)
System.out.print(args.length);

C)
for ( int i = 0; i < 1; i++ ) {

System.out.print(args[i]);


}

D)
None of the above


3. What is the result of the following program, when
you compile and run?

public
class MyTest {


final int x;


public MyTest()
{


System.out.println( x +
10 );


}


public static void main( String args[] )
{

MyTest mt = new MyTest();


}

}

A) Compile
time error

B)
Runtime error

C)
Prints on the screen 10

D)
Throws an exception


4. What is the output when you compile and run the
following code fragment?

class
MyTest {


public void myTest() {

System.out.println(“Printing myTest in MyTest
class”);


}


public static void myStat() {

System.out.println(“Printing myStat in MyTest
class”);


}

}

public
class Test extends MyTest {


public void myTest() {

System.out.println(“Printing myTest in Test
class”);


}


public static void myStat() {

System.out.println(“Printing myStat in Test
class”);


}


public static void main ( String args[] )
{


MyTest mt = new Test();

mt.myTest();

mt.myStat();


}

} 

A) Printing
myTest in MyTest class followed by Printing myStat in MyTest
class

B)
Printing myTest in Test class followed by Printing myStat in MyTest
class

C)
Printing myTest in MyTest class followed by Printing myStat in MyTest
class

D)
Printing myStat in MyTest class followed by Printing myStat in MyTest
class


5. Select
all
 
the exceptions thrown by wait() method of an Object class, which you can
replace in the place of xxx
legally?

class T
implements Runnable {


public void run() {

System.out.println( “Executing run() method”
);

myTest();


}


public synchronized void myTest() {

try {

wait(-1000); 

System.out.println( “Executing the myTest() method” )
;

}  
XXX

}

}

public
class MyTest {


public static void main ( String args[] )
{

T t = new T();

Thread th = new Thread ( t );

th.start();

}

}

A) catch (
InterruptedException ie) {}

B)
catch ( IllegalArgumentException il )
{}

C)
catch ( IllegalMonitorStateException im )
{}

D)
Only catch ( InterruptedException e ) {}
exception


6. Which of the following are examples of immutable
classes , select all correct
answer(s)?

A)
String

B)
StringBuffer

C)
Double

D)
Integer


7. Select the correct answer for the code fragment
given below?

public
class TestBuffer {


public void myBuf( StringBuffer s, StringBuffer s1)
{

s.append(” how are you”) ;


s =
s1;


}


public static void main ( String args[] )
{

TestBuffer tb = new TestBuffer();

StringBuffer s = new
StringBuffer(“Hello”);

StringBuffer s1 = new
StringBuffer(“doing”);

tb.myBuf(s, s1);

System.out.print(s);


}

}

A) Prints
Hello how are you

B)
Prints Hello

C)
Prints Hello how are you doing

D)
Compile time error


8. What is the result when you compile and run the
following code?

public
class MyTest {


public void myTest( int[] increment )
{

increment[1]++;


}


public static void main ( String args[] )
{


int myArray[] = new
int[1]; 


MyTest mt = new
MyTest();

mt.myTest(myArray);

System.out.println(myArray[1]);


}

}

A) Compile
time error

B)
Runtime error

C)
ArrayOutOfBoundsException

D)
Prints 1 on the screen 


9. Chose all  valid
identifiers?

A)
int100

B)
byte

C)
aString

D)
a-Big-Integer

E)
Boolean

F)
strictfp


10. Select the equivalent answer for the code given
below?

boolean b =
true;

if (
b ) {


x =  y;

}
else {


x = z;

}

A) x = b ?
x = y : x = z ;

B) x
= b ? y : z ;

C) b
= x ? y : z ;

D) b
= x ? x = y : x = z ;


11. Chose all correct
answers?

A) int a
[][] = new int [20][20];

B)
int [] a [] = new int [20][];

C)
int [][] a = new int [10][];

D)
int [][] a = new int [][10];


12. Consider the following code and select the
correct answer?

class
Vehicle {


String str ;


public Vehicle()
{


}


public Vehicle ( String s )
{


str = s;


}

}

public
class Car extends Vehicle {


public static void main (String args[] )
{

final Vehicle v = new Vehicle ( ” Hello”
);

v =  new Vehicle ( ” How are
you”);

v.str = “How is going”;


System.out.println( “Greeting is : ”  +
v.str );


}

}

A) Compiler
error while subclassing the Vehicle

B)
Compiler error , you cannot assign a value to  final
variable

B)
Prints Hello

C)
Prints How is going


13. Java source files are concerned  which of
the following are true ?

A) Java
source files can have more than one package
statements.

B)
Contains any number of non-public classes and only one public
class

C)
Contains any number of non-public classes and any number of public
classes

D)
import statements can appear anywhere in the
class

E)
Package statements should appear only in the first line or before any
import statements of source file 


14. Select all correct answers from the
following?

int a =
-1;

int
b = -1;

a
= a >>> 31;

b =
b >> 31;

A) a = 1, b
=1

B) a
= -1, b -1

C) a
= 1, b = 0

D) a
= 1, b = -1


15. What is the value of  a , when you compile
and run the following code?

public
class MyTest {


public static void main ( String args[] )
{

int a =
10;

int
b = 9;

int
c = 7;

a =
a ^ b ^ c;


System.out.println ( a );

}

}

A)
10

B)
9

C)
7

D)
4


16. The following code has some errors, select all
the correct answers from the
following?

public
class MyTest {


public void myTest( int i ) {

for ( int x = 0; x < i; x++ ) {

System.out.println( x ) ;

}

}


public abstract
void Test() {

myTest(10);

}

}

A) At class
declaration

B)
myTest() method declaration

C)
Test() method declaration

D)
No errors, compiles successfully


17. At what point the following code shows compile
time error?

class A
{


A()
{

System.out.println(“Class A
constructor”);

}

}

class B
extends A {


B()
{

System.out.println(“Class B
constructor”);

}

}

public
class C extends A {


C()
{

System.out.println(“Class C
constructor”);

}


public static void main ( String args[] )
{

A a = new A(); // Line 1

A a1 = new B(); // Line 2

A a2 = new C(); // Line 3

B b = new C(); // Line 4

}

}

A) A a =
new A(); // Line 1

B) A
a1 = new B(); // Line 2

C) A
a2 = new C(); // Line 3

D) B
b = new C(); // Line 4


18. Which of the following statements would
return false? if given the following
statements.

String s =
new String (“New year”);


String s1 = new String(“new Year”);

A) s ==
s1

B)
s.equals(s1);

C) s
= s1;

D)
None of the above


19. Select all correct answers about what is the
definition of an interface?

A) It is a
blue print 

B) A
new data type

C)
Nothing but a class definition

D)
To provide multiple inheritance


20. Select all correct answers from the following
code snippets?

A) //
Comments


import
java.awt.*;


package com;

B) import
java.awt.*;


// Comments


package com;

C) package
com;


import
java.awt.*;


// Comments

D)  //
Comments


package
com;


import
java.awt.*;


public class MyTest
{}


21. What is the result when you compile and run the
following code?

public
class MyError {


public static void main ( String args[] )
{

int x = 0;

for ( int i = 0; i < 10; i++ ) {

x = new Math( i );

new System.out.println( x );

}

}

}

A) Prints 0
to 9  in sequence

B)
No output

C)
Runtime error

D)
Compile time error


22. There are two computers are connected to
internet, one computer is trying to open a socket connection to read the
home page of another computer, what are the possible exceptions thrown
while connection and reading
InputStream?.

A)
IOException

B)
MalformedURLException

C)
NetworkException

D)
ConnectException


23. What is the result from the following code when
you run?

import
java.io.*;

class A
{


A() throws Exception {

System.out.println (“Executing class A
constructor”);

throw new IOException();

}

}

public
class B extends A {


B()
{

System.out.println (“Executing class B
constructor”);

}


public
static void main ( String args[] ) {

try {

A a = new B();

} catch ( Exception e) {

System.out.println( e.getMessage() );

}

}

}

A)
Executing class A constructor

B)
Executing class B constructor

C)
Runtime error

D)
Compile time error


24. What is the result from the following code when
you run?

import
java.io.*;

class A
{


A()  {

System.out.println (“Executing class A
constructor”); 

}


A(int a) throws Exception
{

System.out.println (“Executing class A
constructor”);

throw new IOException();

}

}

public
class B extends A {


B()
{

System.out.println (“Executing class B
constructor”);

}


public
static void main ( String args[] ) {

try {

A a = new B();

} catch ( Exception e) {

System.out.println( e.getMessage() );

}

}

}

A)
Executing class A constructor followed by Executing class B
constructor

B)
No output

C)
Runtime error

D)
Compile time error


25. What is the result when you compile and run the
following code?

byte Byte =
10;


byte Double = 12;


byte Integer = Byte * Double;

A)
120;

B)
Compile time error while declaring
variables

C)
Compile time error while
multiplication

D)
None of the above


26. Select all valid methods for Component
class?

A)
setBounds(), setVisible(), setFont()

B)
add(), remove()

C)
setEnabled(), setVisible()


D)addComponent()


27. Which subclasses of the Component class
will display the MenuBar?

A) Window,
Applet

B)
Applet, Panel

C)
Frame

D)
Menu, Dialog


28. Select all correct answers from the following
statements? 

A) Frame’s
default layout manager is
BorderLayout

B)
CheckBox, List are examples of non visual
components

C)
Applets are used to draw custom
drawings

D)
Canvas has no default behavior or
appearance


29. Select all the methods of
java.awt.List?

A) void
addItem(String s), int getRows()

B)
void addItem(String s, int index), void
getRows()

C)
int[] getSelectedIndexes(), int
getItemCount()

D)
int[] getSelectedIndexes(), String[] getSelectedItems()


30. Please select all correct
answers?

A)
java.awt.TextArea.SCROLLBARS_NONE

B)
java.awt.TextArea does not generate Key
events 

C)
java.awt.TextField generates Key events and Action
events

D)
java.awt.TextArea can be scrolled using  the  <– and
–> keys.


31. What is the result if you try to compile and run
the following code ? 

public
class MyTest { 


public static void myTest() {

System.out.println( “Printing myTest() method”
); 


}


public void myMethod() { 


System.out.println(
“Printing myMethod() method” ); 


} 


public static void main(String[] args)
{

myTest();

myMethod(); 


}

}

A) Compile
time error

B)
Compiles successfully 

C)
Error in main method declaration

D)
Prints on the screen Printing myTest() method followed by Printing
myMethod() method


32. What line of a given program will throw
FileNotFoundException?

import
java.io.*;

public
class MyReader {


public static void main ( String args[] )
{

try {

FileReader fileReader = new
FileReader(“MyFile.java”);

BufferedReader bufferedReader = new
BufferedReader(fileReader);

String strString; 

fileReader.close();


while ( ( strString = bufferedReader.readLine()) != null )
{

System.out.println ( strString );

}


} catch ( IOException ie) { 

System.out.println ( ie.getMessage()
);


}


}

}

A) This
program never throws
FileNotFoundException

B)
The line fileReader.close() throws
FileNotFoundException

C)
At instantiation  of FileReader
object.

D)
While constructing the BufferedReader
object


33. When the following  program will throw an
IOException?

import
java.io.*;

class
FileWrite {


public static void main(String
args[]) {

try {

String strString = “Now is the time to take Sun
Certification”;

char buffer[] = new
char[strString.length()];

strString.getChars(0, strString.length(), buffer,
0); 

FileWriter f = new
FileWriter(“MyFile1.txt”);

FileWriter f1 = f;

f1.close();

for (int i=0; i < buffer.length; i += 2)
{

f.write(buffer[i]);

}

f.close();

FileWriter f2 = new
FileWriter(“MyFile2.txt”);

f2.write(buffer);

f2.close();


}
catch ( IOException ie ) {

System.out.println( ie.getMessage());

}


}

}

A) This
program never throws IOException

B)
The line f1.close() throws
IOException

C)
While writing to the stream f.write(buffer[i]) throws an
IOExcpetion

D)
While constructing the FileWriter
object 


34. Which line of the program could be throwing an
exception, if the program is as listed below. Assume that “MyFile2.txt”
is a read only file.

Note:


MyFile2.txt is read only file..

import
java.io.*;

class
FileWrite {


public static void main(String
args[]) {

try {

String strString = “Updating the critical data
section”

char buffer[] = new
char[strString.length()];

strString.getChars(0, strString.length(), buffer,
0); 

FileWriter f = new
FileWriter(“MyFile1.txt”);

FileWriter f1 = f; 

for (int i=0; i < buffer.length; i += 2)
{

f1.write(buffer[i]);

}

f1.close();

FileWriter f2 = new
FileWriter(“MyFile2.txt”);

f2.write(buffer);

f2.close();


}
catch ( IOException ie ) {

System.out.println( ie.getMessage());

}


}

}

A) This
program never throws IOException

B)
The line f1.close() throws
IOException

C)
While writing to the stream f1.write(buffer[i]) throws an
IOException

D)
While constructing the FileWriter f2 = new
FileWriter(“MyFile2.txt”);


35. Select all the correct answers about File
Class? 

A) A File
class can be used to create files and
directories

B) A
File class has a method mkdir() to create
directories

C) A
File class has a method mkdirs() to create directory and its parent
directories

D) A
File cannot be used to create directories


36. Using File class, you can navigate the different
directories and list all the files in the those
directories?

A)
True

B)
False


37. Select all the constructor definitions of
“FileOutputStream”?

A)
FileOutputStream(FileDescriptor fd)

B)
FileOutputStream(String fileName, boolean
append)

C)
FileOutputStream(RandomAccessFile
raFile)

D)
FileOutputStream( String dirName, String
filename)


38. Select all correct answers for Font
class?

A) new Font
( Font.BOLD, 18, 16)

B)
new Font ( Font.SERIF, 24, 18)

C)
new Font ( “Serif”, Font.PLAIN, 24);

D)
new Font ( “SanSerif”, Font.ITALIC,
24);

E)
new Font ( “SanSerif”, Font.BOLD+Font.ITALIC,
24);


39. In an applet programing the requirement is that
, what ever the changes you do in the applets graphics context need to
be accumulated to the previous drawn information. Select all the correct
code snippets?

A) public
void update ( Graphics g) {


paint( g)
;


}

B) public
void update ( Graphics g) {


update( g)
;


}

C) public
void update ( Graphics g) {


repaint( g)
;


}

D) public
void update ( Graphics g) {


print( g)
;


}


40. How can you load the image from the same server
where you are loading the applet, select the correct answer form the
following?

A) public
void init() {


Image
i = getImage ( getDocumentBase(),
“Logo.jpeg”);


}

B) public
void init() {


Image
i = getImage ( “Logo.jpeg”);


}

C) public
void init() {


Image
i = new Image ( “Logo.jpeg”);


}

D) public
void init() {


Image
i = getImage ( new Image( “Logo.jpeg”)
);


}


41. Which of the following answers can be legally
placed in the place of
XXX?

class Check
{


Check() {
}

}

public
class ICheck extends Check {


public static void main ( String[] args)
{


Object o = new
ICheck();


Check i = new
ICheck(); 


Check c = new
Check();


if ( o instanceof 


XXX
)
{

System.out.println(“True”);

} 


}

}

A) Object,
ICheck only

B)
Check , ICheck only

C)
Object only

D)
Object, Check, ICheck


42. There are 20 threads are waiting in the waiting
pool with same priority,  how can you invoke 15th thread from the
waiting pool?.

A) By
calling resume() method

B)
By calling interrupt() method

C)
Calling call() method

D)
By calling notify(15) method on the thread
instance

E)
None of the above


43. Select all the correct answers regarding thread
synchronization ?

A) You can
synchronize entire method

B) A
class can be synchronized

C)
Block of code can be synchronized

D)
The notify() and notifyAll() methods are called only within a
synchronized code


44. The thread run() method has the following code,
what is the result when the thread
runs?

try
{


sleep( 200
);


System.out.println( “Printing from thread run()
method” );

}
catch ( IOException ie) { }

A) Compile
time error

B)
Prints on the console Printing from thread run()
method

C)
At line 2 the thread will be stop running and resumes after 200
milliseconds and prints 


Printing from thread run()
method

D)
At line 2 the thread will be stop running and resumes exactly 200
milliseconds elapsed


45. What is the result when you compile and run the
following code?

import
java.awt.*;

public
class TestBorder extends Frame
{ 


public static void main(String args[])
{ 

Button b = new Button(“Hello”); 

TestBorder t = new
TestBorder(); 

t.setSize(150,150); 

t.add(b); 

} 

} 

A) A Frame
with one big button named Hello

B) A
small button Hello in the center of the
frame

C) A
small button Hello in the right corner of the
frame

D)
Frame does not visible


46. Select all correct answers from the
following?

A) public
abstract void Test() { }

B)
public void abstract Test();

C)
public abstract void Test();

D)
native void doSomthing( int i );


47. Please select all correct statements from the
following?

A)
toString() method is defined in Object
class.

B)
toString() method is defined in Class
class.

C)
wait(), notify(), notifyAll() methods are defined in Object class and
used for Thread communication.

D)
toString() method provides string representation of an Object
state.


48. From the following declarations select all
correct variables/method


declarations? 

Button bt =
new Button (“Hello”);

A) public
transient int val;

B)
public synchronized void Test() ;

C)
bt.addActionListener( new ActionListener ()
);

D)
synchronized ( this ) { 


// Assume that “this”
is  an arbitrary object
instance.


}


49. Which of the following classes will throw
“NumberFormatException”?

A)
Double

B)
Boolean

C)
Integer

D)
Byte


50. Fill all the blanks from the following
?

A)
Math.abs(3.0) returns
3.0


Math.abs(-3.4) returns
——–

B)
Math.ceil(3.4) returns
——–


Math.ceil(-3.4) returns
-3.0 

C)
Math.floor(3.4) returns
——–


Math.ceil(-3.4) returns
-4.0 

D)
Math.round(3.4) returns  3


Math.round(-3.4) returns
——-


51. Select from the following which is legal to put
in the place of XXX?

public
class OuterClass {


private String s = “I am outer class
member variable”;


class InnerClass
{

private String s1 = “I am inner class
variable”;

public void innerMethod() {

System.out.println(s);

System.out.println(s1);

}


}


public static void outerMethod()
{

// XXX legal code here 

inner.innerMethod(); 


}

}

A)
OuterClass.InnerClass inner = new OuterClass().new
InnerClass();

B)
InnerClass inner = new InnerClass();

C)
new InnerClass();

D)
None of the above


52. If you save and compile the following code, it
gives compile time error. How do you correct the compile time
error?

public
class OuterClass {


final String s = “I am outer class member
variable”;


public void Method()
{

String s1 = “I am inner class
variable”;

class InnerClass {

public void innerMethod() { 

int xyz = 20; 

System.out.println(s); 

System.out.println(“Integer value is” +
xyz);

System.out.println(s1);
//
Illegal, compiler error

}

}


}

}

A) By
making s1 as static variable

B)
By making s1 as public variable

C)
By making s1 as final variable

D)
By making  InnerClass as static


53. What is the reason using $ in inner class
representation?

A) Because
the inner classes are defined inside of any
class

B)
Due to the reason that inner classes can be defined inside any
method

C)
This is convention adopted by Sun, to insure that there is no ambiguity
between packages and inner classes.

D)
Because if use getClass().getName() will gives you the
error


54. What is the result when you compile and run the
following code?

import
java.util.*;


public class MyVector {


public Vector myVector () {

Vector v = new Vector();

return v.addElement( “Adding element to
vector”);


}


public static void main ( String [] args)
{

MyVector mv = new MyVector();

System.out.println(mv.myVector());

}

}

A) Prints
Adding element to vector

B)
Compile time error

C)
Runtime error

D)
Compiles and runs successfully


55. What is the output on the screen when compile
and run the following
code? 

public
class TestComp { 

public static void main(String args[])
{ 

int x = 1; 

System.out.println(“The value of x is ”  + (~x >> x)
); 

} 

 }

A)
1

B)
2

C)
-1

D)
-2


56. The method getWhen() is defined in which of the
following class?

A)
AWTEvent

B)
EventObject

C)
InputEvent

D)
MouseEvent


57. Select all correct answers from the
following?

A)
getSource() method is defined in java.awt.AWTEvent
class

B)
getSource() method is defined in java.util.EventObject
class

C)
getID() method is defined in java.awt.AWTEvent
class

D)
getID() method is defined in java.util.EventObject
class


58. Which of the following are correct
answers? 

A) A
listener object is an instance of a class that implements a listener
interface. 

B)
An event source is an object , which can register listener objects and
sends notifications whenever event
occurs. 

C)
Event sources  fires the
events. 

D)
Event listeners fires events.


59. What are possible ways to implement LinkedList
class?

A) As a
HashMap

B)
As a Queue

C)
As a TreeSet

D)
As a Stack 


60. Please select the correct answer from the
following?

public
class ThrowsDemo { 


static void throwMethod() throws Exception
{ 


System.out.println(“Inside
throwMethod.”); 


throw new
IllegalAccessException(“demo”); 


} 


public static void main(String args[])
{ 


try { 

throwMethod(); 


} catch (IllegalAccessException e)
{ 


System.out.println(“Caught ” +
e); 


} 


} 

} 

A)
Compilation error

B)
Runtime error

C)
Compile successfully, nothing is
printed.

D)
inside throwMethod. followed by caught:
java.lang.IllegalAccessException: demo


Answers



Answer 1:

A) Compile
Time error


Explanation:


Generally static methods can be overridden by static methods only ..
Static methods may not be overridden by non static
methods..


Answer 2:

C) for (
int i = 0; i < 1; i++ ) {

System.out.print(args[i]);


}


Explanation:


Answer C) will cause an “ArrayOutOfBoundsException” if you do not pass
the command line arguments to the Java Program. A) and B) will work
without any problem.


Answer 3:

A) Compile
time error


Explanation:

The
final variables behaves like constants, so the final variables must be
initialized before accessing them. They can be initialized where they
are declared or in every “constructor” if the class. ( even if class has
one or more constructors defined ).


Answer
4: 

B) Printing
myTest in Test class followed by Printing myStat in MyTest
class


Explanation:


Static methods are determined at compile time but the non static (
instance methods ) methods are identified at runtime using Run Time Type
Identification ( RTTI).


Answer 5:

A) catch (
InterruptedException ie) {}

B)
catch ( IllegalArgumentException il )
{}

C)
catch ( IllegalMonitorStateException im )
{}


Explanation:

The
wait() method of an Object class throws InterruptedException when the
thread moving from running state to wait state. If the value of timeout
is negative or the value of nanos is not in the range 0-999999 then
wait() method throws IllegalArgumentException exception at runtime. If
the current thread is not the owner of this object’s monitor then it
throws IllegalMonitorStateException exception. Click

here for more information from Java
Documentation. 


Answer
6:

A)
String

C)
Double

D)
Integer


Explanation:


String, Integer, Double are immutable classes, once assign a values it
cannot be changed. Please refer the wrapper classes for more information
on Integer, and Double.


Answer 7:

A) Prints
Hello how are you


Explanation:


Assigning or interchanging the object references does not change the
values, but if you change the values through object references , changes
the values .


Answer 8:

B) Runtime
error

C)
ArrayOutOfBoundsException


Explanation:


This piece of code throws an ArrayOutOfBoundsException at runtime . If
you modify the code int myArray[] = new int[1]; to int myArray[] = new
int[2]; , it prints 1 on the screen. The changes you made on the array
subscript seen by the caller.


Answer 9:

A) int
100

C)
aString

E)
Boolean


Explanation:

The
byte, strictfp are Java keywords and cannot be defined as identifiers,
the a-Big-Integer has “-” which is not a valid identifier. The
identifiers must starts with letters, $, or _ ( underscore), subsequent
characters may be letters, dollar signs, underscores or digits,
any other combination will gives you the compiler
error.


Answer 10:

B) x = b ?
y : z ;


Explanation


If  b is true the value of x is y, else the value is z. This is
“ternary” operator provides the way to simple conditions into a single
expression. If the b is true, the left of ( : ) is assigned to x else
right of the ( : ) is assigned to x. Both  side of the ( : ) must
have the data type.


Answer 11:

A) int a
[][] = new int [20][20];

B)
int [] a [] = new int [20][];

C)
int [][] a = new int [10][];


Explanation:


Multidimensional arrays in Java are just arrays within arrays.
Multidimensional arrays are defined as rows and columns. The outer array
must be initialized. If you look at the answers the outer arrays are
initialized.


Answer 12:

B) Compiler
error , you cannot assign a value to  final
variable


Explanation:

In
Java final variables are treated as constants ( comparing to other
languages like Visual Basic and etc.) ,  once it is initialized you
cannot change the values of primitive, if final variables are object
references then you cannot assign any other
references.


Answer 13:

B) Contains
any number of non-public classes and only one public
class

E)
Package statements should appear only in the first line or before any
import statements of source file 


Explanation:

The
source files always contains only one package statement, you cannot
define multiple package statements and these statements must be before
the import statements. At any point of time Java source files can have
any number of non-public class definitions and only one public
definition class. If you have any import statements those should be
defined before class definition and after the package
definition.


Answer 14:

D) a = 1, b
= -1


Explanation:

The
operator >>> is unsigned right shift, the new bits are set to
zero, so the -1 is shifted 31 times and became 1 ( because a is defined
as integer ). The operator >> is signed right shift operator, the
new bits take the value of the MSB ( Most Significant Bit ) . The
operator << will behave like same as >>> operator. The
sifting operation is applicable to only integer data
types.


Answer 15:

D)
4


Explanation:

The
operator is bitwise XOR operator. The values of a, b, c are first
converted to binary equivalents and calculated using ^ operator and the
results are converted back to original
format.


Answer 16:

C) Test()
method declaration


Explanation:

The
abstract methods cannot have body. In any class if one method is defined
as abstract the class should be defined as abstract class. So in our
example the Test() method must be
redefined.


Answer 17:

D) B b =
new C(); // Line 4


Explanation:


According to the inheritance rules, a parent class references can appear
to the child class objects in the inheritance chain from top to bottom.
But in our example class B, and class C are in the same level of
hierarchy and also these two classes does not have parent and child
relationship which violates the inheritance
rules. 


Answer 18:

A) s ==
s1

B)
s.equals(s1);


Explanation:

The
string objects can be compared for equality using == or the equals()
method ( even though these two have different meaning ). In our example
the string objects have same wording but both are different in case. So
the string object object comparison is case
sensitive.


Answer 19:

A) It is a
blue print 

B) A
new data type

D)
To provide multiple inheritance


Explanation:

One
of the major fundamental change in Java comparing with C++ is
interfaces. In Java the interfaces will provide multiple inheritance
functionality. In Java always a class can be derived from only one
parent, but in C++ a class can derive from multiple
parents.


Answer 20:

C) package
com;


import
java.awt.*;


// Comments

D)  //
Comments


package
com;


import
java.awt.*;


public class MyTest
{}


Explanation

In a
given Java source file, the package statement should be defined before
all the import statement or the first line in the .java file provided if
you do not have any comments or JavacDoc definitions. The sequence of
definitions are: 

// Comments
( if any)


Package definition


Multiple imports


Class definition


Answer 21:

D) Compile
time error


Explanation:

The
code fails at the time Math class instantiation. The java.lang.Math
class is final class and the default constructor defined as private. If
any class has private constructors , we cannot instantiate them from out
the class ( except from another constructor
).


Answer 22:

A)
IOException

B)
MalformedURLException


Explanation:

In
Java the the URL class will throw “MalformedURLException while
construncting the URL, and while reading incoming stream of data they
will throw IOException..


Answer 23:

D) Compile
time error


Explanation:

In
Java the constructors can throw exceptions. If parent class default
constructor is throwing an exception, the derived class default
constructor should handle the exception thrown by the
parent.


Answer 24:

A)
Executing class A constructor followed by Executing class B
constructor


Explanation:

In
Java the constructors can throw exceptions. According to the Java
language exceptions, if any piece of code throwing an exception it is
callers worry is to handle the exceptions thrown by the piece of code.
If parent class default constructor is throwing an exception, the
derived class default constructor should handle the exception thrown by
the parent. But in our example the non default constructor is throwing
an exception if some one calls that constructor they have to handle the
exception.


Answer 25:

C) Compile
time error while multiplication


Explanation:


This does not compile because according to the arithmetic promotion
rules, the *  ( multiplication ) represents binary operator. There
are four rules apply for binary operators. If one operand is
float,double,long then other operand is converted to float,double,long
else the both operands are converted to int data type. So in our example
we are trying put integer into byte which is
illegal. 


Answer 26:

A)
setBounds(), setVisible(), setFont()

B)
add(), remove()

C)
setEnabled(), setVisible()


Explanation:

The
component class is the parent class of all AWT components like Button,
List, Label and etc. Using these methods you can set the properties of
components. The add(), remove() methods are used to add PopMenu and to
remove MenuComponent.


Answer 27:

C)
Frame


Explanation:


Java supports two kinds of menus, pull-down and pop-up menus. Pull-down
menus are accessed are accessed via a menu bar. Menu bars are only added
to Frames.


Answer 28:

A) Frame’s
default layout manager is
BorderLayout

D)
Canvas has no default behavior or
appearance


Explanation:

In
Java AWT each container has it’s own default layout manager implemented
as part of implementation. For example Frame has default layout manager
is BorderLayout , Applet has FlowLayout and etc. The Canvas is kind of
component where you can draw custom drawings. The Canvas generates
Mouse, MouseMotion, and Key events .


Answer 29:

A) void
addItem(String s), int getRows()

C)
int[] getSelectedIndexes(), int
getItemCount()

D)
int[] getSelectedIndexes(), String[] getSelectedItems()


Explanation:

The
java.awt.List has methods to select , count the visible
rows. 


void addItem(String s) –>
adds an item to the bottom of the
list

int
getRows()
–>
returns the number of visible lines in the
list


int[] getSelectedIndexes() –>    returns array of
indexes currently selected items

int
getItemCount()
–>
returns the number of items in the
list


String[] getSelectedItems() –>  returns array of string values
of currently selected items


Answer 30:

A)
java.awt.TextArea.SCROLLBARS_NONE

C)
java.awt.TextField generates Key events and Action
events

D)
java.awt.TextArea can be scrolled using  the  <– and
–> keys.


Explanation:

The
TextArea and TextField are the subclasses of TextComponent class. The
TextArea has static fields to give you the functionality of horizontal
and vertical scroll bars. These are the following
fields:


java.awt.TextArea.SCROLLBARS_BOTH


java.awt.TextArea.SCROLLBARS_NONE


java.awt.TextArea.SCROLLBARS_HORIZONTAL_ONLY


java.awt.TextArea.SCROLLBARS_VERTICAL_ONLY

The
TextArea and TextField will generate Key events and TextField will
generate Action events apart from the Key
events.


Answer 31:

A) Compile
time error


Explanation:

In
Java there are two types of methods , static and non static methods.
Static methods are belong to class and non static methods are belongs to
instances. So from a non static method you can call static as well as
static methods, but from a static method you cannot call non static
methods ( unless create a instance of a class ) but you can call static
methods.


Answer 32:

C) At
instantiation  of FileReader object.


Explanation:


While constructing the FileReader object, if the file is not found in
the file system the “FileNotFoundException” is thrown. If the input
stream is closed before reading the stream throws
IOException.


Answer 33:

C) While
writing to the stream f.write(buffer[i]) throws an
IOException


Explanation:


While writing to a IO stream if the stream is closed before
writing  throws an IOException. In our example the f ( stream ) is
closed via f1 reference variable before writing to
it. 


Answer 34:

D) While
constructing the FileWriter f2 = new
FileWriter(“MyFile2.txt”);


Explanation:


Constructing the FileWriter object, if the file already exists it
overrides it (unless explicitly specified to append to the file).
FileWriter will create the file before opening it for output when you
create the object. In the case of read-only files, if you try to open
and IOException will be thrown.


Answer 35:

A) A File
class can be used to create files and
directories

B) A
File class has a method mkdir() to create
directories

C) A
File class has a method mkdirs() to create directory and its parent
directories.


Explanation:

The
File class has three methods to create empty files, those are
createNewFile(), createTempFile(String prefix, String suffix) and
createTempFile(String prefix, String suffix, File
directory).


File class has two utility methods mkdir() and mkdirs() to create
directories. The mkdir() method creates the directory and returns either
true or false. Returning false indicates that either directory already
exists or directory cannot be created because the entire path does not
exists. In the situation when the path does not exists use the mkdirs()
method to create directory as well as parent directories as
necessary.


Answer 36:

A)
True


Explanation: 


File class can be used to navigate the directories in the underlying
file system. But in the File class there is no way you change the
directory . Constructing the File class instance will always point to
only one particular directory. To go to another directory you may have
to create another instance of a File
class.


Answer 37:

A)
FileOutputStream(FileDescriptor fd)

B)
FileOutputStream(String fileName, boolean
append)


Explanation:

The
valid FileOutputStream constructors are:

  • FileOutputStream(String
    fileName)
  • FileOutputStream(File
    file)
  • FileOutputStream(FileDescriptor
    fd)
  • FileOutputStream(String
    fileName, boolean append)


Answer 38:

C) new Font
( “Serif”, Font.PLAIN, 24);

D)
new Font ( “SanSerif”, Font.ITALIC,
24);

E)
new Font ( “SanSerif”, Font.BOLD+Font.ITALIC,
24);


Explanation:

The
Font class gives you to set the font of a graphics context. While
constructing the Font object you pass font name, style, and size of the
font. The font availability is dependent on platform. The Font class has
three types of font names called ” Serif”, “SanSerif”, Monospaced” these
are called in JDK 1.1 and after “Times Roman”, Helavatica” and
“Courier”.


Answer 39:

A) public
void update ( Graphics g) {


paint( g)
;


}


Explanation:

If
you want accumulate the previous information on the graphics context
override the update() and inside the method call the paint() method by
passing the graphics object as an argument. The repaint() method always
calls update() method


Answer 40:

A) public
void init() {


Image
i = getImage ( getDocumentBase(),
“Logo.jpeg”);


}


Explanation: 

The
Applet and Toolkit classes has a method getImage() , which has two
forms:

  • getImage(URL
    file)
  • getImage(URL dir,
    String file)

These are
two ways to refer an image in the server . The Applet class
getDocumentBase() methods returns the URL object which is your url to
the server where you came from or where your image
resides. 


Answer 41:

D) Object,
Check, ICheck


Explanation:

The
instanceof operator checks the class of an object at runtime. In our
example o refers to Object class and Check and ICheck refers to the
subclasses of Object class. Due to the inheritance hierarchy Check and
ICheck returns true. 


Answer 42:

E) None of
the above


Explanation:


There is no way to call a particular thread from a waiting pool. The
methods notify() will calls thread from waiting pool, but there is no
guaranty which thread is invoked. The method notifyAll() method puts all
the waiting threads from the waiting pool in ready
state. 


Answer 43:

A) You can
synchronize entire method

C)
Block of code can be synchronized

D)
The notify() and notifyAll() methods are called only within a
synchronized code


Explanation:

The
keyword controls accessing the single resource from multiple threads at
the same time. A method or a piece of code can be synchronized, but
there is no way to synchronize a calls. To synchronize a method use
synchronized keyword before method definition. To synchronize block of
code use the synchronized keyword and the arbitrary
instance. 


Answer 44:

A) Compile
time error


Explanation:

The
IOException never thrown here. The exception is thrown is
InterruptedException. To correct instead of catching IOException use
InterruptedException.


Answer 45:

D) Frame
does not visible


Explanation:

The
Frame is not going to be visible unless you call setVisible(true) method
on the Frame’s instance. But the frame instance is available in
computers memory. If do not set the size of the Frame you see default
size of the frame ( i.e.. in minimized
mode)


Answer 46:

C) public
abstract void Test();

D)
native void doSomthing( int i );


Explanation:

The
abstract methods does not have method bodies. In any  given class
if one method is defined as abstract the class must defined as abstract
class. 


Answer 47:

A)
toString() method is defined in Object
class.

C)
wait(), notify(), notifyAll() methods are defined in Object class and
used for Thread communication.

D)
toString() method provides string representation of an Object
state.


Explanation:

The
toString() is defined in Object class the parent all classes which will
gives you the string representation of the object’s state. This more
useful for debugging purpose. The wait(), notify(), notifyAll() methods
are also defined in Object class are very helpful for Thread
communication. These methods are called only in synchronized
methods.


Answer 48:

A) public
transient int val;

D)
synchronized ( this ) { 


// Assume that “this”
is  an arbitrary object
instance.


}


Explanation:

To
define transient variables just include “transient” keyword in the
variable definition. The transient variables are not written out any
where, this is the way when you do object serialization not to write the
critical data to a disk or to a database.

The
“synchronized” keyword controls the single resource not to access by
multiple threads at the same time. The synchronized keyword can be
applied to a method or to a block of code by passing the arbitrary
object instance name as an argument.


Answer 49:

A)
Double

C)
Integer

D)
Byte


Explanation: 

In
Java all the primitive data types has wrapper classes to represent in
object format and will throw “NumberFormatException”. The Boolean does
not throw “NumberFormatException” because while constructing the wrapper
class for Boolean which accepts string also as an
argument.


Answer 50:

A)
Math.abs(3.0) returns
3.0


Math.abs(-3.4) returns
3.4

B)
Math.ceil(3.4) returns
4.0


Math.ceil(-3.4) returns
-3.0 

C)
Math.floor(3.4) returns
3.0


Math.floor(-3.4) returns
-4.0 

D)
Math.round(3.4) returns   3


Math.round(-3.4) returns
-3


Explanation:

The
Math class abs() method returns the absolute values, for negative values
it just trips off the negation and returns positive absolute value. This
method returns always double value.

The method
ceil(), returns double value not less than the integer ( in our case 3
). The other ways to say this method returns max integer value . ( All
the decimals are rounded to 1 and is added to integer value ). For
negative values it behaves exactly
opposite.

The method
floor() is exactly reverse process of  what ceil() method
does.

The round()
method just rounds to closest integer
value.


Answer 51:

A)
OuterClass.InnerClass inner = new OuterClass().new
InnerClass();


Explanation:

The
static methods are class level methods to execute those you do not need
a class instance. If you try to execute any non static method or
variables from static methods you need to have instance of a class. In
our example we need to have OuterClass reference to execute InnerClass
method.


Answer 52:

C) By
making s1 as final variable


Explanation:

In
Java it is possible to declare a class inside a method. If you do this
there are certain rules will be applied to access the variables of
enclosing class and enclosing methods. The classes defined inside any
method can access only final variables of enclosing
class.


Answer 53:

C) This is
convention adopted by Sun , to insure that there is no ambiguity between
packages and inner classes.


Explanation:


This is convention adopted to distinguish between packages and inner
classes. If you try to use Class.forName() method the call will fail
instead use getCLass().getName() on an instance of inner
class.


Answer 54:

B) Compile
time error


Explanation:

The
method in Vector class , addElement() returns type of void which you
cannot return in our example. The myVector() method in our MyVector
class returns only type of Vector.


Answer 55:

C)
-1


Explanation:


Internally the x value first gets inverted ( two’s compliment ) and then
shifted 1 times. First when it is inverted it becomes negative value and
shifted by one bit.


Answer 56:

C)
InputEvent


Explanation:

The
InputEvent class has method getWhen() which returns the time when the
event took place and the return type is
long. 


Answer 57:

B)
getSource() method is defined in java.util.EventObject
class

C)
getID() method is defined in java.awt.AWTEvent
class


Explanation:

The
super class of  all event handling is java.util.EventObject which
has a method called getSource() , which returns the object that
originated the event. 

The
subclass of EventObject is AWTEvent has a method getID() , which returns
the ID of the event which specifies the nature of the
event.


Answer 58:

A) A
listener object is an instance of a class that implements a listener
interface. 

B)
An event source is an object , which can register listener objects and
sends notifications whenever event
occurs. 

C)
Event sources  fires the
events. 


Explanation:

The
event listeners are instance of the class that implements listener
interface . An event source is an instance of class like Button or
TextField that can register listener objects and sends notifications
whenever event occurs.


Answer 59:

B) As a
Queue

D)
As a Stack 


Explanation:


This implements java.util.List interface and uses linked list for
storage. A linked list allows elements to be added, removed from the
collection at any location in the container by ordering the elements.
With this implementation you can only access the elements in
sequentially.You can easily treat the LinkedList as a stack, queue and
etc., by using the LinkedList
methods. 


Answer 60:

A)
Compilation error


Explanation:

The
method throwMethod() is throwing and type Exception class instance,
while catching the exception you are catching the subclass of Exception
class.

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