SUN CERTIFIED PROGRAMMER FOR THE JAVA 2 PLATFORM
EXAM QUESTION AND ANSWER
QUESTION: 61
A
company has a business application that provides its users with many different
reports: receivables reports, payables reports, revenue projects, and so on.
The company has just purchased some new, state-of-the-art, wireless printers,
and a programmer has been assigned the task of enhancing all of the reports to
use not only the company's old printers, but the new wireless printers as well.
When the programmer starts looking into the application, the programmer
discovers that because of the design of the application, it is necessary to
make changes to each report to support the new printers.Which two design concepts
most likely explain this situation?
(Choose
two.)
A.
Inheritance
B.
Low cohesion
C.
Tight coupling
D.
High cohesion
E.
Loose coupling
F.
Object immutability
Answer: B,C
QUESTION: 62
Given:
10.
public class SuperCalc {
11.
protected static int multiply(int a, int b) { return a * b;}
12.
}
and:
20.
public class SubCalc extends SuperCalc{
21.
public static int multiply(int a, int b) {
22.
int c = super.multiply(a, b);
23.
return c;
24.
}
25.
}
and:
30.
SubCalc sc = new SubCalc ();
31.
System.out.println(sc.multiply(3,4));
32.
System.out.println(SubCalc.multiply(2,2));
What
is the result?
A.
124
B.
The code runs with no output.
C.
An exception is thrown at runtime.
D.
Compilation fails because of an error in line 21.
E.
Compilation fails because of an error in line 22.
F.
Compilation fails because of an error in line 31.
Answer: E
QUESTION: 63
Given:
31.
class Foo {
32.
public int a = 3;
33.
public void addFive() { a += 5; System.out.print("f "); }
34.
}
35.
class Bar extends Foo {
36.
public int a = 8;
37.
public void addFive() { this.a += 5; System.out.print("b " ); }
38.
}
Invoked
with:
Foo
f = new Bar();
f.addFive();
System.out.println(f.a);
What
is the result?
A.
b 3
B.
b 8
C.
b 13
D.
f 3
E.
f 8
F.
f 13
G.
Compilation fails.
H.
An exception is thrown at runtime.
Answer: A
QUESTION: 64
A
company that makes Computer Assisted Design (CAD) software has,within its
application,some utility classes that are used to perform 3D rendering tasks. The
company's
chief scientist has just improved the performance of one of the utility
classes'key rendering algorithms, and has assigned a programmer to replace the
old algorithm with the new algorithm. When the programmer begins researching
the utility classes, she is happy to discover that the algorithm to be replaced
exists in only one class. The programmer reviews that class's API, and replaces
the old algorithm with the new algorithm, being careful that her changes adhere
strictly to the class's API. Once testing has begun, the programmer discovers
that other classes that use the class she changed are no longer working
properly. What design flaw is most likely the cause of these new bugs?
A.
Inheritance
B.
Tight coupling
C.
Low cohesion
D.
High cohesion
E.
Loose coupling
F.
Object immutability
Answer: B
QUESTION: 65
Given:
1.
class ClassA {
2.
public int numberOfInstances;
3.
protected ClassA(int numberOfInstances) {
4.
this.numberOfInstances = numberOfInstances;
5.
}
6.
}
7.
public class ExtendedA extends ClassA {
8.
private ExtendedA(int numberOfInstances) {
9.
super(numberOfInstances);
10.
}
11.
public static void main(String[] args) {
12.
ExtendedA ext = new ExtendedA(420);
13.
System.out.print(ext.numberOfInstances);
14.
}
15.
}
Which
statement is true?
A.
420 is the output.
B.
An exception is thrown at runtime.
C.
All constructors must be declared public.
D.
Constructors CANNOT use the private modifier.
E.
Constructors CANNOT use the protected modifier.
Answer: A
QUESTION: 66
Given:
11.
class ClassA {}
12.
class ClassB extends ClassA {}
13.
class ClassC extends ClassA {}
and:
21.
ClassA p0 = new ClassA();
22.
ClassB p1 = new ClassB();
23.
ClassC p2 = new ClassC();
24.
ClassA p3 = new ClassB();
25.
ClassA p4 = new ClassC();
Which
three are valid? (Choose three.)
A.
p0 = p1;
B.
p1 = p2;
C.
p2 = p4;
D.
p2 = (ClassC)p1;
E.
p1 = (ClassB)p3;
F.
p2 = (ClassC)p4;
Answer: A,E,F
QUESTION: 67
Given:
5.
class Thingy { Meter m = new Meter(); }
6.
class Component { void go() { System.out.print("c"); } }
7.
class Meter extends Component { void go() { System.out.print("m"); }
}
8.
9.
class DeluxeThingy extends Thingy {
10.
public static void main(String[] args) {
11.
DeluxeThingy dt = new DeluxeThingy();
12.
dt.m.go();
13.
Thingy t = new DeluxeThingy();
14.
t.m.go();
15.
}
16.
}
Which
two are true? (Choose two.)
A.
The output is mm.
B.
The output is mc.
C.
Component is-a Meter.
D.
Component has-a Meter.
E.
DeluxeThingy is-a Component.
F.
DeluxeThingy has-a Component.
Answer: A,F
QUESTION: 68
Given:
10.
interface Jumper { public void jump(); }
...
20.
class Animal {}
...
30.
class Dog extends Animal {
31.
Tail tail;
32.
}
...
40.
class Beagle extends Dog implements Jumper{
41.
public void jump() {}
42.
}
...
50.
class Cat implements Jumper{
51.
public void jump() {}
52.
}
Which
three are true? (Choose three.)
A.
Cat is-a Animal
B.
Cat is-a Jumper
C.
Dog is-a Animal
D.
Dog is-a Jumper
E.
Cat has-a Animal
F.
Beagle has-a Tail
G.
Beagle has-a Jumper
Answer: B,C,F
QUESTION: 69
Given:
1.
import java.util.*;
2.
public class WrappedString {
3.
private String s;
4.
public WrappedString(String s) { this.s = s; }
5.
public static void main(String[] args) {
6.
HashSet<Object> hs = new HashSet<Object>();
7.
WrappedString ws1 = new WrappedString("aardvark");
8.
WrappedString ws2 = new WrappedString("aardvark");
9.
String s1 = new String("aardvark");
10.
String s2 = new String("aardvark");
11.
hs.add(ws1); hs.add(ws2); hs.add(s1); hs.add(s2);
12.
System.out.println(hs.size()); } }
What
is the result?
A.
0
B.
1
C.
2
D.
3
E.
4
F.
Compilation fails.
G.
An exception is thrown at runtime.
Answer: D
QUESTION: 70
Given:
11.
// insert code here
12.
private N min, max;
13.
public N getMin() { return min; }
14.
public N getMax() { return max; }
15.
public void add(N added) {
16.
if (min == null || added.doubleValue() < min.doubleValue())
17.
min = added;
18.
if (max == null || added.doubleValue() > max.doubleValue())
19.
max = added;
20.
}
21.
}
Which
two, inserted at line 11, will allow the code to compile? (Choose two.)
A.
public class MinMax<?> {
B.
public class MinMax<? extends Number> {
C.
public class MinMax<N extends Object> {
D.
public class MinMax<N extends Number> {
E.
public class MinMax<? extends Object> {
F.
public class MinMax<N extends Integer> {
Answer: D,F
QUESTION: 71
Given:
3.
import java.util.*;
4.
public class G1 {
5.
public void takeList(List<? extends String> list) {
6.
// insert code here
7.
}
8.
}
Which
three code fragments, inserted independently at line 6, will compile? (Choose
three.)
A.
list.add("foo");
B.
Object o = list;
C.
String s = list.get(0);
D.
list = new ArrayList<String>();
E.
list = new ArrayList<Object>();
Answer: B,C,D
QUESTION: 72
Given
that the elements of a PriorityQueue are ordered according to natural ordering,
and:
2.
import java.util.*;
3.
public class GetInLine {
4.
public static void main(String[] args) {
5.
PriorityQueue<String> pq = new PriorityQueue<String>();
6.
pq.add("banana");
7.
pq.add("pear");
8.
pq.add("apple");
9.
System.out.println(pq.poll() + " " + pq.peek());
10.
}
11.
}
What
is the result?
A.
apple pear
B.
banana pear
C.
apple apple
D.
apple banana
E.
banana banana
Answer: D
QUESTION: 73
Given
a pre-generics implementation of a method:
11.
public static int sum(List list) {
12.
int sum = 0;
13.
for ( Iterator iter = list.iterator(); iter.hasNext(); ) {
14.
int i = ((Integer)iter.next()).intValue();
15.
sum += i;
16.
}
17.
return sum;
18.
}
Which
three changes must be made to the method sum to use generics? (Choose three.)
A.
Remove line 14.
B.
Replace line 13 with "for (int i : intList) {".
C.
Replace line 13 with "for (Iterator iter : intList) {".
D.
Replace the method declaration with "sum(List<int> intList)".
E.
Replace the method declaration with "sum(List<Integer>
intList)".
Answer: A,B,E
QUESTION: 74
Given:
enum
Example { ONE, TWO, THREE }
Which
statement is true?
A.
The expressions (ONE == ONE) and ONE.equals(ONE) are both guaranteed to be
true.
B.
The expression (ONE < TWO) is guaranteed to be true and ONE.compareTo(TWO)
is guaranteed
to be less than one.
C.
The Example values cannot be used in a raw java.util.HashMap; instead, the
programmer
must use a java.util.EnumMap.
D.
The Example values can be used in a java.util.SortedSet, but the set will NOT
be
sorted
because enumerated types do NOT implement java.lang.Comparable.
Answer: A
QUESTION: 75
Given:
3.
import java.util.*;
4.
public class Mapit {
5.
public static void main(String[] args) {
6.
Set<Integer> set = new HashSet<Integer>();
7.
Integer i1 = 45;
8.
Integer i2 = 46;
9.
set.add(i1);
10.
set.add(i1);
11.
set.add(i2); System.out.print(set.size() + " ");
12.
set.remove(i1); System.out.print(set.size() + " ");
13.
i2 = 47;
14.
set.remove(i2); System.out.print(set.size() + " ");
15.
}
16.
}
What
is the result?
A.
2 1 0
B.
2 1 1
C.
3 2 1
D.
3 2 2
E.
Compilation fails.
F.
An exception is thrown at runtime.
Answer: B
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QUESTION: 76
Given:
12.
import java.util.*;
13.
public class Explorer1 {
14.
public static void main(String[] args) {
15.
TreeSet<Integer> s = new TreeSet<Integer>();
16.
TreeSet<Integer> subs = new TreeSet<Integer>();
17.
for(int i = 606; i < 613; i++) 18. if(i%2 == 0) s.add(i);
19.
subs = (TreeSet)s.subSet(608, true, 611, true);
20.
s.add(609);
21.
System.out.println(s + " " + subs);
22.
}
23.
}
What
is the result?
A.
Compilation fails.
B.
An exception is thrown at runtime.
C.
[608, 609, 610, 612] [608, 610]
D.
[608, 609, 610, 612] [608, 609, 610]
E.
[606, 608, 609, 610, 612] [608, 610]
F.
[606, 608, 609, 610, 612] [608, 609, 610]
Answer: F
QUESTION: 77
Given:
3.
import java.util.*;
4.
public class Quest {
5.
public static void main(String[] args) {
6.
String[] colors = {"blue", "red", "green",
"yellow", "orange"};
7.
Arrays.sort(colors);
8.
int s2 = Arrays.binarySearch(colors, "orange");
9.
int s3 = Arrays.binarySearch(colors, "violet");
10.
System.out.println(s2 + " " + s3);
11.
}
12.
}
What
is the result?
A.
2 -1
B.
2 -4
C.
2 -5
D.
3 -1
E.
3 -4
F.
3 -5
G.
Compilation fails.
H.
An exception is thrown at runtime.
Answer: C
QUESTION: 78
Given:
34.
HashMap props = new HashMap();
35.
props.put("key45", "some value");
36.
props.put("key12", "some other value");
37.
props.put("key39", "yet another value");
38.
Set s = props.keySet();
39.
// insert code here
What,
inserted at line 39, will sort the keys in the props HashMap?
A.
Arrays.sort(s);
B.
s = new TreeSet(s);
C.
Collections.sort(s);
D.
s = new SortedSet(s);
Answer: B
QUESTION: 79
Which
two statements are true? (Choose two.)
A.
It is possible to synchronize static methods.
B.
When a thread has yielded as a result of yield(), it releases its locks.
C.
When a thread is sleeping as a result of sleep(), it releases its locks.
D.
The Object.wait() method can be invoked only from a synchronized context.
E.
The Thread.sleep() method can be invoked only from a synchronized context.
F.
When the thread scheduler receives a notify() request, and notifies a thread,
that thread immediately
releases its lock.
Answer:
A,D
QUESTION:
80
Given:
7.
void waitForSignal() {
8.
Object obj = new Object();
9.
synchronized (Thread.currentThread()) {
10.
obj.wait();
11.
obj.notify();
12.
}
13.
}
Which
statement is true?
A.
This code can throw an InterruptedException.
B.
This code can throw an IllegalMonitorStateException.
C.
This code can throw a TimeoutException after ten minutes.
D.
Reversing the order of obj.wait() and obj.notify() might cause this method to
complete normally.
E.
A call to notify() or notifyAll() from another thread might cause this method
to
complete
normally.
F.
This code does NOT compile unless "obj.wait()" is replaced with
"((Thread)
obj).wait()".
Answer: B
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