SCJP Questions 151-160

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Question 151
Click the Exhibit button.
1. public class SimpleCalc {
2. public int value;
3. public void calculate() { value += 7; }
4. }
And:
1. public class MultiCalc extends SimpleCalc {
2. public void calculate() { value -= 3; }
3. public void calculate(int multiplier) {
4. calculate();
5. super.calculate();
6. value *=multiplier;
7. }
8. public static void main(String[] args) {
9. MultiCalc calculator = new MultiCalc();
10. calculator.calculate(2);
11. System.out.println(”Value is: “+ calculator.value);
12. }
13. }
What is the result?
A. Value is: 8
B. Compilation fails.
C. Value is: 12
D. Value is: -12
E. The code runs with no output.
F. An exception is thrown at runtime.
Answer: A

Question 152
Given:
10. public class Hello {
11. String title;
12. int value;
13. public Hello() {
14. title += “ World”;
15. }
16. public Hello(int value) {
17. this.value = value;
18. title = “Hello”;
19. Hello();
20. }
21. }
and:
30. Hello c = new Hello(5);
31. System.out.println(c.title);
What is the result?
A. Hello
B. Hello World
C. Compilation fails.
D. Hello World 5
E. The code runs with no output.
F. An exception is thrown at runtime.
Answer: C

Question 153
Click the Exhibit button.
1. public class Car {
2. private int wheelCount;
3. private String vin;
4. public Car(String vin) {
5. this.vin = vin;
6. this.wheelCount = 4;
7. }
8. public String drive() {
9. return “zoom-zoom”;
10. }
11. public String getInfo() {
12. return “VIN: “+ vin + “wheels: “+ wheelCount;
13. }
14. }
And:
1. public class MeGo extends Car {
2. public MeGo(String vin) {
3. this.wheelCount = 3;
4. }
5. }
What two must the programmer do to correct the compilation errors?
(Choose two.)
A. insert a call to this() in the Car constructor
B. insert a call to this() in the MeGo constructor
C. insert a call to super() in the MeGo constructor
D. insert a call to super(vin) in the MeGo constructor
E. change the wheelCount variable in Car to protected
F. change line 3 in the MeGo class to super.wheelCount = 3;
Answer: DE

Question 154
Click the Exhibit button.
1. public class Employee {
2. String name;
3. double baseSalary;
4. Employee(String name, double baseSalary) {
5. this.name = name;
6. this.baseSalary = baseSalary;
7. }
8. }
And:
1. public class Salesperson extends Employee {
2. double commission;
3. public Salesperson(String name, double baseSalary,
4. double commission) {
5. // insert code here
6. }
7. }
Which code, inserted at line 7, completes the Salesperson constructor?
A. this.commission = commission;
B. superb();
commission = commission;
C. this.commission = commission;
superb();
D. super(name, baseSalary);
this.commission = commission;
E. super();
this.commission = commission;
F. this.commission = commission;
super(name, baseSalary);
Answer: D

Question 155
Given:
1. public class Blip {
2. protected int blipvert(int x) { return 0; }
3. }
4. class Vert extends Blip {
5. // insert code here
6. }
Which five methods, inserted independently at line 5, will compile?
(Choose five.)
A. public int blipvert(int x) { return 0; }
B. private int blipvert(int x) { return 0; }
C. private int blipvert(long x) { return 0; }
D. protected long blipvert(int x) { return 0; }
E. protected int blipvert(long x) { return 0; }
F. protected long blipvert(long x) { return 0; }
G. protected long blipvert(int x, int y) { return 0; }
Answer: ACEFG

Question156
Given:
10. public class Foo {
11. public int a;
12. public Foo() { a = 3; }
13. public void addFive() { a += 5; }
14. }
and:
20. public class Bar extends Foo {
21. public int a;
22. public Bar() { a = 8; }
23. public void addFive() { this.a +=5; }
24. }
invoked with:
30. Foo foo = new Bar();
31. foo.addFive();
32. System.out.println(”Value: “+ foo.a);
What is the result?
A. Value: 3
B. Value: 8
C. Value: 13
D. Compilation fails.
E. The code runs with no output.
F. An exception is thrown at runtime.
Answer: A

Question 157
Given:
10. public class SuperCaic {
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. 12
4
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 158
Given:
1. public class Team extends java.util.LinkedList {
2. public void addPlayer(Player p) {
3. add(p);
4. }
5. public void compete(Team opponent) { /* more code here */ }
6. }
7. class Player { /* more code here */ }
Which two are true? (Choose two.)
A. This code will compile.
B. This code demonstrates proper design of an is-a relationship.
C. This code demonstrates proper design of a has-a relationship.
D. A Java programmer using the Team class could remove Player
objects from a Team object.
Answer: AD

Question 159
Which four are true? (Choose four.)
A. Has-a relationships should never be encapsulated.
B. Has-a relationships should be implemented using inheritance.
C. Has-a relationships can be implemented using instance variables.
D. Is-a relationships can be implemented using the extends keyword.
E. Is-a relationships can be implemented using the implements
keyword.
F. The relationship between Movie and Actress is an example of an is-a
relationship.
G. An array or a collection can be used to implement a one-to-many
has-a relationship.
Answer: CDEG

Question 160
Which two are true about has-a and is-a relationships? (Choose two.)
A. Inheritance represents an is-a relationship.
B. Inheritance represents a has-a relationship.
C. Interfaces must be used when creating a has-a relationship.
D. Instance variables can be used when creating a has-a relationship.
Answer: AD

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