#45 to #51 SCJP/OCJP Exams Questions & Answers-

45. Given:

1. public class A {

2. public void doit() {

3. }

4. public String doit() {

5. return "a";

6. }

7. public double doit(int x) {

8. return 1.0;

9. }

10. }

What is the result?

A. An exception is thrown at runtime.

B. Compilation fails because of an error in line 7.

C. Compilation fails because of an error in line 4.

D. Compilation succeeds and no runtime errors with class A occur.

Answer: C

46. Given:

35. String #name = "Jane Doe";

36. int $age = 24;

37. Double _height = 123.5;

38. double ~temp = 37.5;

Which two statements are true? (Choose two.)

A. Line 35 will not compile.

B. Line 36 will not compile.

C. Line 37 will not compile.

D. Line 38 will not compile.

Answer: A,D

47. Given:

10. interface Foo { int bar(); }

11. public class Sprite {

12. public int fubar( Foo foo ) { return foo.bar(); }

13. public void testFoo() {

14. fubar(

15. // insert code here

16. );

17. }

18. }

Which code, inserted at line 15, allows the class Sprite to compile?

A. Foo { public int bar() { return 1; }

B. new Foo { public int bar() { return 1; }

C. new Foo() { public int bar() { return 1; }

D. new class Foo { public int bar() { return 1; }

Answer: C

48. Given:

11. public enum Title {

12. MR("Mr."), MRS("Mrs."), MS("Ms.");

13. private final String title;

14. private Title(String t) { title = t; }

15. public String format(String last, String first) {

16. return title + " " + first + " " + last;

17. }

18. }

19. public static void main(String[] args) {

20. System.out.println(Title.MR.format("Doe", "John"));

21. }

What is the result?

A. Mr. John Doe

B. An exception is thrown at runtime.

C. Compilation fails because of an error in line 12.

D. Compilation fails because of an error in line 15.

E. Compilation fails because of an error in line 20.

Answer: A

49. Given the following six method names:

addListener

addMouseListener

setMouseListener

deleteMouseListener

removeMouseListener

registerMouseListener

How many of these method names follow JavaBean Listener naming rules?

A. 1

B. 2

C. 3

D. 4

E. 5

Answer: B

50. Given:

10. class Line {

11. public static class Point {}

12. }

13.

14. class Triangle {

15. // insert code here

16. }

Which code, inserted at line 15, creates an instance of the Point class defined in Line?

A. Point p = new Point();

B. Line.Point p = new Line.Point();

C. The Point class cannot be instatiated at line 15.

D. Line l = new Line() ; l.Point p = new l.Point();

Answer: B

51. Given

11. public interface Status {

12. /* insert code here */ int MY_VALUE = 10;

13. }

Which three are valid on line 12? (Choose three.)

A. final

B. static

C. native

D. public

E. private

F. abstract

G. protected

Answer: A,B,D

#35 to #44 SCJP/OCJP Exams Questions & Answers-

35. Given:

22. StringBuilder sb1 = new StringBuilder("123");

23. String s1 = "123";

24. // insert code here

25. System.out.println(sb1 + " " + s1);

Which code fragment, inserted at line 24, outputs "123abc 123abc"?

A. sb1.append("abc"); s1.append("abc");

B. sb1.append("abc"); s1.concat("abc");

C. sb1.concat("abc"); s1.append("abc");

D. sb1.concat("abc"); s1.concat("abc");

E. sb1.append("abc"); s1 = s1.concat("abc");

F. sb1.concat("abc"); s1 = s1.concat("abc");

G. sb1.append("abc"); s1 = s1 + s1.concat("abc");

H. sb1.concat("abc"); s1 = s1 + s1.concat("abc");

Correct Answer: E

36. Which code, inserted at line 14, will allow this class to correctly serialize and deserialize?

import 

1.Import java.io.*;

2.public class foo implements Serialisable{

3.public int x,y;

4.public Foo(int x,int y){this.x=x;

    this.y=y;

5.  }

6.private void writeObject(

  ObjectOutputsStream s)

7.  throws IOException{

8.s.writeInt(x);

9. s.writeInt(y);

10.}

11.private void readObject(ObjectInputStream)

12 .throws IOException,ClassNotFoundException

13.{

14.//insert code here

15.

16.}

17.}

A. s.defaultReadObject();

B. this = s.defaultReadObject();

C. y = s.readInt(); x = s.readInt();

D. x = s.readInt(); y = s.readInt();

Correct Answer: D

37. Given:

1. public class LineUp {

2. public static void main(String[] args) {

3. double d = 12.345;

4. // insert code here

5. }

6. }

Which code fragment, inserted at line 4, produces the output | 12.345|?

A. System.out.printf("|%7d| \n", d);

B. System.out.printf("|%7f| \n", d);

C. System.out.printf("|%3.7d| \n", d);

D. System.out.printf("|%3.7f| \n", d);

E. System.out.printf("|%7.3d| \n", d);

F. System.out.printf("|%7.3f| \n", d);

Correct Answer: F

38. Given:

11. public class Test {

12. public static void main(String [] args) {

13. int x = 5;

14. boolean b1 = true;

15. boolean b2 = false;

16.

17. if ((x == 4) && !b2 )

18. System.out.print("1 ");

19. System.out.print("2 ");

20. if ((b2 = true) && b1 )

21. System.out.print("3 ");

22. }

23. }

What is the result?

A. 2

B. 3

C. 1 2

D. 2 3

E. 1 2 3

F. Compilation fails.

G. An exception is thrown at runtime.

Correct Answer: D

39. Given:

10. interface Foo {}

11. class Alpha implements Foo {}

12. class Beta extends Alpha {}

13. class Delta extends Beta {

14. public static void main( String[] args ) {

15. Beta x = new Beta();

16. // insert code here

17. }

18. }

Which code, inserted at line 16, will cause a java.lang.ClassCastException?

A. Alpha a = x;

B. Foo f = (Delta)x;

C. Foo f = (Alpha)x;

D. Beta b = (Beta)(Alpha)x;

Correct Answer: B

40. Given:

22. public void go() {

23. String o = "";

24. z:

25. for(int x = 0; x < 3; x++) {

26. for(int y = 0; y < 2; y++) {

27. if(x==1) break;

28. if(x==2 && y==1) break z;

29. o = o + x + y;

30. }

31. }

32. System.out.println(o);

33. }

What is the result when the go() method is invoked?

A. 00

B. 0001

C. 000120

D. 00012021

E. Compilation fails.

F. An exception is thrown at runtime.

Correct Answer: C

41.Given:

11. static void test() throws RuntimeException {

12. try {

13. System.out.print("test ");

14. throw new RuntimeException();

15. }

16. catch (Exception ex) { System.out.print("exception "); }

17. }

18. public static void main(String[] args) {

19. try { test(); }

20. catch (RuntimeException ex) { System.out.print("runtime "); }

21. System.out.print("end ");

22. }

What is the result?

A. test end

B. Compilation fails.

C. test runtime end

D. test exception end

E. A Throwable is thrown by main at runtime.

Correct  Answer: D

42. Given:

33. try {

34. // some code here

35. } catch (NullPointerException e1) {

36. System.out.print("a");

37. } catch (Exception e2) {

38. System.out.print("b");

39. } finally {

40. System.out.print("c");

41. }

If some sort of exception is thrown at line 34, which output is possible?

A. a

B. b

C. c

D. ac

E. abc

Correct  Answer: D

43. Given:

31. // some code here

32. try {

33. // some code here

34. } catch (SomeException se) {

35. // some code here

36. } finally {

37. // some code here

38. }

Under which three circumstances will the code on line 37 be executed? (Choose three.)

A. The instance gets garbage collected.

B. The code on line 33 throws an exception.

C. The code on line 35 throws an exception.

D. The code on line 31 throws an exception.

E. The code on line 33 executes successfully.

Correct Answer: B,C,E

44. Given:

10. int x = 0;

11. int y = 10;

12. do {

13. y--;

14. ++x;

15. } while (x < 5);

16. System.out.print(x + "," + y);

What is the result?

A. 5,6

B. 5,5

C. 6,5

D. 6,6

Correct Answer: B

#30 to #34 SCJP/OCJP Exams Questions & Answers-

30. Given a valid DateFormat object named df, and

16. Date d = new Date(0L);

17. String ds = "December 15, 2004";

18. // insert code here

What updates d's value with the date represented by ds?

A. 18. d = df.parse(ds);

B. 18. d = df.getDate(ds);

C. 18. try {

   19. d = df.parse(ds);

   20. } catch(ParseException e) { };

D. 18. try {

   19. d = df.getDate(ds);

   20. } catch(ParseException e) { };

Correct  Answer: C

31. Given:

11. double input = 314159.26;

12. NumberFormat nf = NumberFormat.getInstance(Locale.ITALIAN);

13. String b;

14. //insert code here

Which code, inserted at line 14, sets the value of b to 314.159,26?

A. b = nf.parse( input );

B. b = nf.format( input );

C. b = nf.equals( input );

D. b = nf.parseObject( input );

Correct  Answer: B

32. Given:

1. public class TestString1 {

2. public static void main(String[] args) {

3. String str = "420";

4. str += 42;

5. System.out.print(str);

6. }

7. }

What is the output?

A. 42

B. 420

C. 462

D. 42042

E. Compilation fails.

F. An exception is thrown at runtime.

Correct  Answer: D

33. Which capability exists only in java.io.FileWriter?

A. Closing an open stream.

B. Flushing an open stream.

C. Writing to an open stream.

D. Writing a line separator to an open stream.

Correct  Answer: D

34. Given that the current directory is empty, and that the user has read and write permissions, and the following:

11. import java.io.*;

12. public class DOS {

13. public static void main(String[] args) {

14. File dir = new File("dir");

15. dir.mkdir();

16. File f1 = new File(dir, "f1.txt");

17. try {

18. f1.createNewFile();

19. } catch (IOException e) { ; }

20. File newDir = new File("newDir");

21. dir.renameTo(newDir);

22. }

23. }

Which statement is true?

A. Compilation fails.

B. The file system has a new empty directory named dir.

C. The file system has a new empty directory named newDir.

D. The file system has a directory named dir, containing a file f1.txt.

E. The file system has a directory named newDir, containing a file f1.txt.

Correct Answer: E

#25 to #29 SCJP/OCJP Exams Questions & Answers-

25 Given:

11. abstract class Vehicle { public int speed() { return 0; }

12. class Car extends Vehicle { public int speed() { return 60; }

13. class RaceCar extends Car { public int speed() { return 150; }

...

21. RaceCar racer = new RaceCar();

22. Car car = new RaceCar();

23. Vehicle vehicle = new RaceCar();

24. System.out.println(racer.speed() + ", " + car.speed()

25. + ", " + vehicle.speed());

What is the result?

A. 0, 0, 0

B. 150, 60, 0

C. Compilation fails.

D. 150, 150, 150

E. An exception is thrown at runtime.

Correct Answer: D

26  A team of programmers is reviewing a proposed API for a new utility class. After some discussion, they realize that they can reduce the number of methods in the API without losing any functionality. If they implement the new design , which two OO principles will they be promoting?

A. Looser coupling

B. Tighter coupling

C. Lower cohesion

D. Higher cohesion

E. Weaker encapsulation

F. Stronger encapsulation

Correct Answer: A

27  Given:

5. class Building { }

6. public class Barn extends Building {

7. public static void main(String[] args) {

8. Building build1 = new Building();

9. Barn barn1 = new Barn();

10. Barn barn2 = (Barn) build1;

11. Object obj1 = (Object) build1;

12. String str1 = (String) build1;

13. Building build2 = (Building) barn1;

14. }

15. }

Which is true?

A. If line 10 is removed, the compilation succeeds.

B. If line 11 is removed, the compilation succeeds.

C. If line 12 is removed, the compilation succeeds.

D. If line 13 is removed, the compilation succeeds.

E. More than one line must be removed for compilation to succeed.

Correct Answer: C

28  Given:

21. class Money {

22. private String country = "Canada";

23. public String getC() { return country; }

24. }

25. class Yen extends Money {

26. public String getC() { return super.country; }

27. }

28. public class Euro extends Money {

29. public String getC(int x) { return super.getC(); }

30. public static void main(String[] args) {

31. System.out.print(new Yen().getC() + " " + new Euro().getC());

32. }

33. }

What is the result?

A. Canada

B. null Canada

C. Canada null

D. Canada Canada

E. Compilation fails due to an error on line 26.

F. Compilation fails due to an error on line 29.

Correct Answer: E

29  Assuming that the serializeBanana() and the deserializeBanana() methods will correctly

use Java serialization and given:

13. import java.io.*;

14. class Food implements Serializable {int good = 3;}

15. class Fruit extends Food {int juice = 5;}

16. public class Banana extends Fruit {

17. int yellow = 4;

18. public static void main(String [] args) {

19. Banana b = new Banana(); Banana b2 = new Banana();

20. b.serializeBanana(b); // assume correct serialization

21. b2 = b.deserializeBanana(); // assume correct

22. System.out.println("restore "+b2.yellow+ b2.juice+b2.good);

24. }

25. // more Banana methods go here

50. }

What is the result?

A. restore 400

B. restore 403

C. restore 453

D. Compilation fails.

E. An exception is thrown at runtime.

Correct Answer: C