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SCJP 1.4 Mock Exam – 15



























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































1

Which of the following can prevent a
thread from executing?





(1)

A call to its pause method

(2)

A call to Thread.yield()

(3)

Another thread is given higher
priority


(4)

A call to its halt() method






Answer :
————————-






2

Which of the following represent
correct syntax for assertions?





(1)

assertion(b==false);

(2)

assert (b==false);

(3)

assert() b==false;

(4)

if(b!=true) assert;






Answer :
————————-






3

What will happen if you attempt to
compile and run the following code?


public class Master{
boolean bContinue=false;
public static void main(String argv[]){
Master m = new Master();
m.go();
}
public void go(){
Slave s = new Slave(this);
Thread t1 = new Thread(s);
t1.start();
while(bContinue==false){
}
s.setPrice(200);
}
}

class Slave implements Runnable{
int iPrice =100;
Master master;
Slave(Master m){
master=m;
}
synchronized public void setPrice(int iM){
iPrice=iM;
}

synchronized public void run(){
master.bContinue=true;
while(true){
System.out.println(iPrice);
}

}
}








(1)

Compilation but no output as the run
method of slave is not correct


(2)

Compilation and output of 100
several times followed by 200 several times


(3)

Compilation and repeated output of
100


(4)

Compile time error, while cannot be
given an unconditional boolean value







Answer :
————————-






4

What will happend when you attempt
to compile and run the following code?


public class Tux extends Thread{
static String sName = “Techno”;
public static void main(String argv[]){
Tux t = new Tux();
t.name(sName);
System.out.println(sName);
}
public void name(String sName){
sName = sName + ” park”;
start();
}
public void run(){
for(int i=0;i < 4; i++){
sName = sName + ” ” + i;
}
}
}








(1)

Compile time error

(2)

Compilation and output of “Techno
park”


(3)

Compilation and output of “Techno
park 0 1 2 3”


(4)

Compilation and probably output of
“Techno” but possible output of “Techno 0 1 2 3”







Answer :
————————-






5

Which of the following require
explicit try/catch exception handling by the programmer?





(1)

Traversing each member of an
array


(2)

Attempting to open a file

(3)

Attempting to open a network
socket


(4)

Accessing a method in other
clas







Answer :
————————-






6

What will be the result when you
attempt to compile this program?


public class RandomExample{
public static void main(String argv[]){
int iRand;
iRand = Math.random();
System.out.println(iRand);
}
}








(1)

Compile time error referring to a
cast problem


(2)

A random number between 1 and
10


(3)

A random number between 0 and
1


(4)

A compile time error about random
being an unrecognised method







Answer :
————————-






7

Which of the following statements
are true?





(1)

The vaue of the Integer class can be
changed using the = operator


(2)

The value of the Integer class can
be changed using the setValue method


(3)

The value of the Integer class can
be changed using the setInt method


(4)

Once assigned the value of an
instance of Integer cannot be changed







Answer :
————————-






8

What will happen when you attempt to
compile and run the following code?


import java.util.*;
public class TechnoExample{
public static void main(String argv[]){
TechnoExample junk = new TechnoExample();
junk.sampleMap();
}
public void sampleMap(){
TreeMap tm = new TreeMap();
tm.put(“a”,”Bill”);
tm.put(“b”,”Kathy”);
tm.put(“c”,”Carl”);
Iterator it = tm.keySet().iterator();
while(it.hasNext()){
System.out.print(tm.get(it.next()));
}
}
}








(1)

Compile time error, a19 cannot be
used as a method name


(2)

Compilation and output of
BillKathyCarl


(3)

Compilation and output of
BillCarlKathy


(4)

Compilation and output of abc






Answer :
————————-






9

What will happen when you attempt to
compile and run the following code?


class Biddy{
public Biddy(){
System.out.print(” Biddy “);
}
}
class Val extends Biddy{
public Val(){
System.out.print(” Val “);
}
}

public class BluePeter extends Val{
public static void main(String argv[]){
BluePeter bp = new BluePeter();
bp.shep(3);
}
public void shep(float i){
System.out.println(i);
}
}








(1)

Compilation and output of Val Biddy
3


(2)

Compilation and output of Val Biddy
3.0


(3)

Compilation and output of Biddy Val
3.0


(4)

Compile time error, wrong parameter
type passed to method shep







Answer :
————————-






10

which of the following statements
are true of the ArrayList class?





(1)

It can store primitive or references
as elements


(2)

It implements the List
interface


(3)

It has a get(int index)
method which returns the element at the specified position in the
list


(4)

The elements are ordered but not
sorted







Answer :
————————-






11

What will happen when you attempt to
compile and run the following code?


class Base{
public int iAcres=3;
}
public class Mfields extends Base{
private int iAcres=3.5;
public static void main(String args[]){
Base mf = new Mfields();
System.out.println(mf.iAcres);
}
}








(1)

Compile time error

(2)

Compilation and output fo 3.5

(3)

Compilation and output of 3

(4)

Compilation but no output at
runtime







Answer :
————————-






12

Which of the following statements
are true?





(1)

A variable declared as public within
a method will always be visible from code anywhere else in the
class


(2)

A variable declared as public at
class level will always be visible from code anywhere else in the
class


(3)

A method with no visibility modifier
can be less visible than one declared with the protected modifier


(4)

Only one copy will ever exist of a
method variable declared as static







Answer :
————————-






13

Which of the following are valid
uses of the assert statement?





(1)

assert();

(2)

assert {

int > 0;

}


(3)

assert(iMonth < 12);

(4)

assert (iAge = 0);






Answer :
————————-






14

At what point will the object
created on line 8 be eligible for garbage collection?


1 public class RJMould{
2 StringBuffer sb;
3 public static void main(String argv[]){
4 RJMould rjm = new RJMould();
5 rjm.kansas();
6 }
7 public void kansas(){
8 sb = new StringBuffer(“Manchester”);
9 StringBuffer sb2 = sb;
10 StringBuffer sb3 = new StringBuffer(“Chester”);
11 sb=sb3;
12 sb3=null;
13 sb2=null;
14 }
15 }








(1)

Line 11

(2)

Line 9

(3)

Line 12

(4)

Line 13






Answer :
————————-






15

What will happen when you attempt to
compile and run the following code?


public class HarHam{
public static void main(String argv[]){
HarHam hh = new HarHam();
hh.go();
}
public void go(){
String har = new String (“har”);
String ham = new String(“har”);

collar:
for(int i=0; i < 2 ; i ++){
if(har==ham){
break collar;
}

if(i > 0){
continue collar;
}
System.out.print(i);
} // for i
}
}








(1)

Compile time error, System.out has
no print method


(2)

No output at runtime

(3)

Output of 0

(4)

Compile error, break cannot occur
after its target label







Answer :
————————-






16

What will happen when you attempt to
compile the following code?


protected class Wmid{
private Wmid(String sName){
System.out.println(“Wmid”);
}

Wmid(){}
}

public class Ombers extends Wmid{
public static void main(String argv[]){
Ombers o = new Ombers();
}

}








(1)

Compile time error, class Wmid may
not be marked as protected


(2)

Compile time error, a constructor
may not be marked as private


(3)

Compilation and output of
Wmid


(4)

Compilation but no output






Answer :
————————-






17

What will happen when you attempt to
compile and run the following code?


public class Mickle extends Thread implements Runnable{
public static void main(String argv[]){
Mickle m = new Mickle();
m.start();

}
public void run(){
go();
}
public void go(){
int i;
while(true){
try{
wait();
System.out.println(“interrupted”);
}catch (InterruptedException e) {}
}
}
}








(1)

Compile time error

(2)

Compilation but runtime
exception


(3)

Compilation but no output at
runtime


(4)

Compilation and output of
“interrupted” at runtime







Answer :
————————-






18

Which of the following statements
are true?





(1)

A LinkedHashMap preserves the order
in which objects are added


(2)

A TreeMap ensures that its elements
will be in sorted order


(3)

Elements in a LinkedList are sorted
but not ordered


(4)

Collections that implement the List
interface allow duplicate elements







Answer :
————————-






19

Select one correct statement about
the following code.


public class TechnoSample {
public static void main(String[] args) {
int i=3;
System.out.println(getBoolean()? i=2*i++:i+++ ++i);
}

public static boolean getBoolean(){
if((int)(Math.random()*2)==0)
return false;
else
return true;
}
}








(1)

Prints randomly 6 or 8 at each
execution


(2)

Prints randomly 7 or 8 at each
execution


(3)

Always prints 6 at each
execution


(4)

Prints randomly 6 or 11 at each
execution


(5)

Compilation error






Answer :
————————-






20

An ArithmeticException is a checked
exception. True Or False?





(1)

True

(2)

False






Answer :
————————-






21

Assume the bit pattern of byte x is:
10110001. What will the sign of x be after x >> 2? Fill with
positive Or negative. Caution: No spaces or extra characters.










Answer :
————————-






22

In a switch statement, the argment
to the case label (case argument:) can be any variable which can fit
within an int. True/False?





(1)

True

(2)

False






Answer :
————————-






23

Overloaded methods must not throw
new checked exceptions not thrown by the original method. True/False?





(1)

True

(2)

False






Answer :
————————-






24

Which of the following statements
are true?





(1)

Assigning null to a reference causes
the object to be garbage collected


(2)

Assigning null to a reference causes
the object to become eligable for garbage collection


(3)

An object is eligable for garbage
collection once it is unreachable via any reference


(4)

Any object created within a method
will be eligable for garbage collection once the method ceases
execution







Answer :
————————-






25

Which of the following statements
are true about the LinkedHashSet class?





(1)

It may not contain duplicate
elements


(2)

The elements are ordered but not
sorted


(3)

The elements are sorted

(4)

It does not permit null
elements







Answer :
————————-






26

Given the following code, which
option if inserted after the line with the comment //Here will result in
code that will compile and output SupEx?

 
class Super{
public void go(){
System.out.print(“Super”);
}

}

public class SupEx extends Super{
public static void main(String argv[]){
//Here
s.go();
}
public void go(){
System.out.println(“SupEx”);
}
}








(1)

SupEx s = new Super();

(2)

Super s = new SupEx();

(3)

SupEx s = new SupEx();

(4)

Super s = new Super();






Answer :
————————-






27

Which of the following will result
in an output of 10?





(1)

System.out.println(Math.round(10.1));

(2)

System.out.println(Math.floor(10.1));

(3)

System.out.println(Math.abs(10.1));

(4)

System.out.println(Math.min(10.1));






Answer :
————————-






28

Given this code, which of the
following statements are true?


public class Photos {
private int iKey;
private String sValue;

public Photos(int iKey, String sValue){
this.iKey=iKey;
this.sValue=sValue;
}

public int hashCode(){
return super.hashCode();
}

public boolean equals(Object o){
if(o instanceof Photos){
if(this.hashCode() == o.hashCode()){
return true;
}
}
return false;
}
}








(1)

The hashCode method is correctly
implemented


(2)

The hashCode method is not correct
because it is inconsistant with the equals method


(3)

The code will not compile because
there is a circular reference to the hashCode method


(4)

The code will not compile because
the return value of this.hashCode is not an int value


(5)

The code will not compile because it
does not implement the comparable interface







Answer :
————————-






29

Which of the following statements
are true?





(1)

A higher priority Thread will
prevent a lower priorty Thread from getting any access to the CPU


(2)

The yield method only allows any
higher priority priority thread to execute


(3)

The Thread class has a static method
called yield


(4)

Calling yield with an integer
parameter causes it to yield for a specific time







Answer :
————————-






30

How do you set the priority of the
thread “newThread” to the minimum of two values: maximum priority and
current priority incremented to the next level. [Use the Thread priority
constants and do not insert any extra characters or leave any blank
spaces]










Answer :
————————-






31

Variables declared within methods
cannot be marked as static. True/False?





(1)

True

(2)

False






Answer :
————————-






32

What is the initial capacity of an
empty StringBuffer object?

ie., new StringBuffer()

[No extra characters Or spaces]










Answer :
————————-






33

What is the capacity of strBuf
object after executing the following statement?

    StringBuffer strBuf = new StringBuffer(“Technopark”);








(1)

0

(2)

6

(3)

25

(4)

255

(5)

-1

(6)

None of the above






Answer :
————————-






34

How can you remove the superfluous
capacity of a StringBuffer object say strBuf (if there is any)?

(Hint: Use SetLength() and length() methods. Please do not include any
extra characters Or spaces)










Answer :
————————-






35

What will be the result of
attempting to compile and run the following code?



public class MyClass
{
public static void main(String[] args)
{
String s = “hello”;
StringBuffer sb = new StringBuffer(s);

sb.reverse();

if (s == sb)
System.out.println(“a”);
if (s.equals(sb))
System.out.println(“b”);
if (sb.equals(s))
System.out.println(“c”);
}
} // MyClass



(1)

The code will fail to compile, since
the constructor of the String class is not properly called


(2)

The code will fail to compile, since
(s == sb) is an illegal expression


(3)

The code will fail to compile, since
the expression (s.equals(sb)) is illegal


(4)

The code will print c when
run


(5)

The program will throw a
ClassCastException when run







Answer :
————————-






36

At which point will the word
“Harpic” be printed out when this code is executied?


class Harpic{
public void finalize(){
System.out.println(“Harpic”);
}

}

public class ArmitageShanks{
Harpic har;
public static void main(String argv[]){
ArmitageShanks as = new ArmitageShanks();
as.oui();
}
public void oui(){
har = new Harpic();
mno(har);
//one
har=null;

}
public void mno(Harpic har){
Harpic pic=har;
//two
pic=null;
//three
har=null;
}
}








(1)

After executing the line after the
comment //one


(2)

After executing the line after the
comment //two


(3)

After executing the line after the
comment //three


(4)

It is impossible to say, the String
“Harpic” may not be output at all







Answer :
————————-






37

What will happen when you attempt to
compile and run the following code?


class TSamp extends Thread {
public native String getTime();
}

public class Multi implements Runnable {
boolean bStop;
public static void main(String argv[]){
Multi m = new Multi();
m.go();
}
public void go(){
TSamp ts = new TSamp(this);
ts.start();
bStop=true;

}
public void run(){
if(bStop==true){
return;
}
System.out.println(“running”);
}
}








(1)

Compilation, but output at runtime
will cannot be exactly determined


(2)

Compilation and output of
“running”


(3)

Compilation but no output at
runtime


(4)

Compile time error






Answer :
————————-






38

What will happen if you compile the
following code with assertions enabled?


public class Cote{
public static void main(String argv[]){
Cote c = new Cote();
c.go(argv[0]);
}
public void go(String s){
int i = Integer.parseInt(s);
if(i > 0){
System.out.println(i);
}else{
throw new AssertionError(i);
}
}
}








(1)

Compile time error, AssertionError
has no int constructor


(2)

Compile time error AssertionError
does not exist


(3)

Assertion Error at runtime if given
a command line parameter of 0


(4)

If given a command line parameter of
1, 1 will be output at runtime







Answer :
————————-






39

What will happen if you attempt to
compile and run the following code?


import java.util.*;
public class Chawson{
public static void main(String argv[]){
Chawson c = new Chawson();
c.whittan();
}
public void whittan(){
HashSet hs = new HashSet();
hs.add(“one”);
hs.add(“two”);
hs.add(“one”);
wyche(hs);
}
public void wyche(Set s){
HashSet hs = (HashSet) s;
System.out.println(hs.size());
}
}








(1)

Compilation and output of 3

(2)

Compile time error, duplicate
elements cannot be added to HashSet


(3)

Runtime error due to an attempt to
add duplicate elements to a HashSet


(4)

Compilation and output of 2






Answer :
————————-






40

AssertionError exceptions are
checked exceptions. True Or False?





(1)

True

(2)

False






Answer :
————————-






41

What will the output be when the
following method is executed?


public static void main(String[] args ){
int n = 11 ;
do {
System.out.print( ” ” + n– );
}while( (n % 4) != 0 );
System.out.println( ” final ” + n );
}








(1)

11 10 9 final 8

(2)

10 9 8 final 8

(3)

11 10 9 8 final 8

(4)

11 final 10






Answer :
————————-






42

Consider the following main method
in the TechnoSample class:


public static void main (String[] args){
String s1 = ” Arg ” + args[1] ;
s1.trim();
String s2 = “:” + s1 + args[2] ;
System.out.println( s2 + “:” );
}




What will be printed when this is executed with the following command
line?



java TechnoSample alpha beta gamma delta









(1)

:Arg betagamma:

(2)

:Argbetagamma:

(3)

: Arg betagamma:

(4)

: Arg alphabeta:

(5)

:Arg alphabeta:






Answer :
————————-






43

What will happen when you attempt to
compile and run the following code?

class WornPadException extends RuntimeException{

}

public class Wheel{

public static void main(String argv[]){

Wheel w = new Wheel();

System.out.print(w.roll());

}

public int roll(){

int iDistance =0;

try{

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

System.out.print(“roll”);

iDistance = iDistance * i;

}

return iDistance;

}finally{

brake();

System.out.print(“finished”);

return iDistance+1;

}

}

public void brake() throws WornPadException{

System.out.print(“brake”);

}

}





(1)

Compile time error, calls to brake
must be within a try/catch block


(2)

Compile time error the try block has
no catch clause


(3)

Runtime error, the call to brake is
not within a try/catch block


(4)

Runtime error the call to brake is
within a finally clause


(5)

Compilation and output of
rollrollbrakefinished0


(6)

Compilation and output of
rollrollbrakefinished1







Answer :
————————-






44

Select all of the following
statements that are true.





(1)

The Float class has constructors
that take type String, type double and type float


(2)

The * operator can be used to
multiply the values of instances of the Integer class


(3)

The setValue method can be used to
alter the value of an instance of Integer, Float or Double


(4)

The Character class can store either
a char value or a String value


(5)

The Integer.parseInt method will
convert an appropriate String to its int value







Answer :
————————-






45

When programming a local inner class
inside a method code block, which of the following statements is true?
Check all which apply.





(1)

The inner class will only have
access to static variables in the enclosing class


(2)

The inner class can use any local
variables declared in the method


(3)

The only local variables an inner
class can use are those that are declared final


(4)

The only local variables an inner
class can use are those that are declared static


(5)

The inner class will only have
access to instance and local variables if they are declared final







Answer :
————————-






46

Which of the following are public
variables or methods that belong to an instance of Thread?

Do not select static variables, static methods, or deprecated methods.









(1)

wait() method

(2)

sleep() method

(3)

start() method

(4)

MAX_PRIORITY – an int
variable


(5)

daemon – a boolean variable






Answer :
————————-






47

Which of the following is not a Java
keyword? (Java SDK v1.4)





(1)

transient

(2)

generic

(3)

assert

(4)

strictfp

(5)

friend

(6)

sizeof






Answer :
————————-






48

Consider the variables declared in
the following code:


public class TechnoSample{

static Object theObj ;
static Object[] someObj ;
static String letters[] = {“A”, “B”, “C”, “D” };
static char[] caps = {‘A’, ‘B’, ‘C’, ‘D’ };

public static void main (String[] args){
someObj = new Object[ 3 ] ;
int[] theInts = null ;
// what can go here?
}




Select statements that could replace the comment without causing a
compiler error.





(1)

theInts = caps;

(2)

theObj = theInts;

(3)

someObj = theInts;

(4)

theObj = caps;






Answer :
————————-






49

What will happen when we try to
compile and run this code?


1 public void testC(char ch) {
2 Integer ss = new Integer( ch );
3 Character cc = new Character( ch ) ;
4 if( ss.equals( cc )) System.out.println(“equals”);
5 if( ss.intValue() == cc.charValue() ){
6 System.out.println(“EQ”);
7 }
8 }








(1)

The compiler will object to line 4
because the object types of ss and cc don’t match


(2)

The program will compile and run,
producing “EQ”


(3)

The program will compile and run,
producing “equalsEQ”


(4)

The program will compile and run,
producing “equals”


(5)

The compiler will object to creating
an Integer from a char in line 2







Answer :
————————-






50

Your program has two object
references, x and y. In some method the following logical tests are
done:


boolean hashFlag = ( x.hashCode() == y.hashCode() );
boolean equalsFlag = x.equals( y );
boolean eqFlag = ( x == y );




Which of the following statements about the relationship between these
tests are true.





(1)

If equalsFlag is true, then hashFlag
must be true


(2)

If hashFlag is true, then eqFlag
must be true


(3)

If equalsFlag is false, then eqFlag
must be false


(4)

if hashFlag is false, then eqFlag
must be false







Answer :
————————-









 



1] 2,3



Explanation:

pause() and halt() are not methods of the Thread class.





* * * *






2] 2



Explanation:

Please see the Java 1.4 documentation.





* * * *






3] 2



Explanation:

Although bContinue does get set to true, the setPrice call is blocked because
setPrice and run are both synchronized.





* * * *






4] 4



Explanation:

If that seems a vauge answer it is because you cannot be certain of the system
that the underlying OS uses for allocating cycles for a Thread. The chances
are that once the thread has been spun off in the call to start in the
methodname() the main method will run to completion and the value of sName
will still be vandeluer before the Thread modifies it. You cannot be certain
of this though.



Just because sName is static does not mean that passing it to a method gives
the method the original copy. The method only sees a locally created copy and
any changes to it will not be reflected on return to the calling method.





* * * *






5] 2,3



Explanation:

Generally speaking, all I/O operations require explicit exception handling
with try/catch blocks. The JDK 1.4 exams does not explicitly cover I/O but it
may be referred to in the context of exception handling.





* * * *






6] 1



Explanation:

This is a bit of a sneaky one as the Math.random method returns a pseudo
random number between 0 and 1, and thus option 3 is a plausible Answer.
However the number returned is a double and so the compiler will complain that
a cast isneeded to convert a double to an int.





* * * *






7] 4



Explanation:

All wrapper class objects are immutable.





* * * *






8] 2



Explanation:

The TreeMap class stores the keys rather than the values in sorted order.





* * * *






9] 3



Explanation:

Constructors are executed in order of the oldest ancester down, so the output
from Biddy is seen before Val. Although the the paremeter for shep has no
floating point component, a widening conversion involves no loss of
precisionand thus the value is cast to a float by the method shep. By default
a float will have a decimal component and thus it has a trailing zero in this
example.





* * * *






10] 2,3,4



Explanation:

Please see Java 1.2/1.4 API documentation.





* * * *






11] 1



Explanation:

An int cannot have a fractional component, under JDK1.4 this produced the
error message



possible loss of precision found : double required: int

private int iAcres=3.5;





* * * *






12] 2,3



Explanation:

A variable declared as public within a method is only visible within the
method. They are sometimes called automatic variables as they automatically
come into scope when the method runs and are out of scope when the method
hasfinished execution. Variables declared within methods cannot be marked as
static. A method declared with no visibility modifier is accessible anywhere
from within the current package.A method declared with the protected modifier
is also accessible in child classes that are not in the current package.





* * * *






13] 3



Explanation:

Option 4 is incorrect because an assert statment must make a comparison and
the single = sign indicates an assignment.The assert statement does not use
curly braces and assert cannot be used like a parameterless method call as in
assert() in option 1.





* * * *






14] 4



Explanation:

On line 9 the object created on line 8 has the reference sb2 pointed to it.
Until something happens to make that reference unable to reach the object it
will not be eligible for garbage collection.





* * * *






15] 3



Explanation:

The == operator should never be used to test the equivalence of strings as it
will only test the reference, not the sequence of characters. To test if the
Strings match use the String equals() method.





* * * *






16] 1



Explanation:

There is no rule against constructors being marked as private.





* * * *






17] 2



Explanation:

This code will produce a java.lang.IllegalMonitorStateException at
runtime because the wait/notify code is not within synchronized code.





* * * *






18] 1,2,4



Explanation:

The LinkedHashMap was added with JDK1.4. Option 3 is nonsense because if
something is sorted that imposes an order (however something may be ordered
without being sorted).





* * * *






19] 1



Explanation:

No problem here, the code compiles fine. One thing to be aware of is that i+++
++i compiles fine because of the way Java code is actually parsed. The parser
tokenizes the source in bunches of longest valid character sequences. i+++ ++i
will betokenized as i,++,+,++,i and interpreted as i++ + ++i, that is i
post-incremented plus i pre-incremented. Then you have to know how the ternary
conditional ?: operator works, that is, it always evaluates its first operand
and then depending onthe results, evaluates the second OR the third operand
(never both). So getBoolean() returns either true or false, thus the code
either prints i=2*i++ or i+++ ++i. The former is equivalent to i=2*i and the
latter to 2*i+2.





* * * *






20] 2



Explanation:

ArithmeticExceptions are considered programmer problems, and are not checked
by the compiler. A divide-by-zero error, for example, should be checked for by
your own code. (from Java Ranch round up game)





* * * *






21] negative



Explanation:

The right shift operator fills all bits from the left with the same value as
the original sign bit — in this case 1. (from Java Ranch round up
game)






* * * *






22] 2



Explanation:

The case argument must be either an int literal, or an int-compatible variable
which is a constant ie., static final.





* * * *






23] 2



Explanation:

This would be true for overriding methods, but overloaded methods are free to
throw new checked exceptions. (from Java Ranch)





* * * *






24] 3



Explanation:

Assigning null to a reference will only cause the object it references to be
ready for garbage collection if no other reference points to it.It is possible
to create an object inside a method and to also assign a reference created
outside the method to the same object,so the completion of a method is no
guarantee that an object is eligable for garbage collection.





* * * *






25] 1,2



Explanation:

Please see the relevant API.





* * * *






26] 2,3



Explanation:

—





* * * *






27] 1



Explanation:

Options 2 will output 10.0 and option 3 will output 10.1. Option 4 will cause
a compilation error, because the Math.min method takes two arguments (from
www.examulator.com)






* * * *






28] 1



Explanation:

This represents a fairly useless but correct implementation of hashCode by
using the version inherited from Object which uses the memory address of the
object to generatethe hashCode value. (from www.examulator.com)





* * * *






29] 3



Explanation:

A call to yield can allow any waiting thread to execute depending on the
scheduling system of the underlying operating system. There is no version of
yield that takes aninteger parameter.Weather a higher priority thread gets CPU
time than a lower priorty thread is platform dependent and cannot be certain.
(from www.examulator.com)





* * * *






30]
newThread.setPriority(Math.min(Thread.MAX_PRIORITY,newThread.getPriority()+1));



Explanation:

—





* * * *






31] 1



Explanation:

—





* * * *






32] 16



Explanation:

The default capacity for any StringBuffer object is 16 + the length of the
String specified as the argument. If none specified, it will be 16. Capacity
can also be specifiedusing the other constructor StringBuffer(int capacity).





* * * *






33] 3



Explanation:

Capacity of a StringBuffer object is always the length of the string + 16
(unless the capacity is specified using StringBuffer(int capacity))





* * * *






34] strBuf.setLength(strBuf.length());



Explanation:

Please see the StringBuffer API.





* * * *






35] 2



Explanation:

The expression tries to compare two references and will fail, since neither
String nor StringBuffer is a super class of the other [from Khalid’s
book
]





* * * *






36] 4



Explanation:

The instance of the Harpic class will probably not be garbage collected at
all, and thus the finalize method will not be run (but it could be).(from
www.examulator.com)






* * * *






37] 4



Explanation:

The TSamp has no constructor defined that takes a class of type Runnable, and
as constructors are not inherited the code will not compile. (from
www.examulator.com)






* * * *






38] 3,4



Explanation:

—





* * * *






39] 4



Explanation:

Because the code attempts to insert the string “one” twice, the HashSet hs has
only two elements.

It is a good idea when using the add method of HashSet to check the boolean
value returned to ensure that the new element wassuccessfully added.





* * * *






40] 2



Explanation:

java.lang.AssertionError class is a subclass of java.lang.Error and that makes
it unchecked.





* * * *






41] 1



Explanation:

Note that n is decremented after the value is printed. (from LanWrights
exam
)





* * * *






42] 3



Explanation:

The result is “: Arg betagamma:” because the call to trim() does not change
s1. (from LanWrights exam)





* * * *






43] 6



Explanation:

Choice 1 & 2 are not correct, ’cause WornPadException extends
RuntimeException it is not mandatory to surround calls to it with a try/catch
block. Choice 3 is not correct since thecompiler checks the need for
try/catch, not the runtime. Choice 4 is not correct, because a finally clause
can have any code in it. Choice 5 is not correct, since the final
valuereturned is 1. Choice 6 is correct because WornPadException extends
RuntimeException it is not mandatory to surround calls to it with a try/catch
block. It is perfectly correct &sometimes useful to have a try/finally
block without a catch statement. Because the finally clause ‘ll be executed
the value returned ‘ll be that within the finally clause.





* * * *






44] 1,5



Explanation:

Facts:

The * operator can only work with primitives. The value in a wrapper class
object can’t be changed once created. The Character class can only store a
char value.(from LanWrights exam)





* * * *






45] 3



Explanation:

Only local variables declared final can be used by the inner class. (from
LanWrights exam
)





* * * *






46] 1,3



Explanation:

Since wait is a method in Object and Thread is an object; sleep is a static
method; start is an instance method of Thread; MAX_PRIORITY is a static final
variable of Thread;the daemon boolean variable is a private instance variable.
(from LanWrights exam)





* * * *






47] 2,5,6



Explanation:

transient is used as a modifier for variables; generic is not a keyword; as of
Java 1.4, assert is a keyword; the keyword strictfp controls floating point
calculations; friend is nota keyword; Java does not use sizeof.





* * * *






48] 2,4



Explanation:

you can’t cast any primitive array to another primitive array type, no matter
how reasonable it seems; any array can be cast to an Object reference; you
can’t cast a primitive arrayto an reference type array. The compiler does not
care that theInts will have a null value when the program runs. (from
LanWrights exam
)





* * * *






49] 2



Explanation:

the equals method is defined in terms of taking an Object reference so there
is no problem; the equals test fails because the objects are of different
types, but the charValuereturn is promoted to int and the result is true; the
equals test fails because the objects are of different types; only the ==
comparison will result in true. Note that the compilerpromotes the charValue
return to int; promotion of the char value to int is automatic. (Credit:
LanWrights
)





* * * *






50] 1,3,4



Explanation:

(1) yes, this is a requirement for hashcodes and the equals method; (2) no,
two objects not equal by the == test may still have identical hashcodes (3)
Yes, if the equals() testreturns false, x and y can’t possibly refer to the
same object (4) Yes, this is a requirement for hashcodes and the equals
method. (Credit: LanWrights)





* * * *

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