Test Bank Answers Inheritance Chapter 10

Starting Out with Java: From Control Structures through Objects 7e (Gaddis)

Chapter 10 Inheritance

TRUE/FALSE

1. Because every class directly or indirectly inherits from the Object class, every class inherits the Object class's members.

2. If a method in a subclass has the same signature as a method in the superclass, the subclass method overrides the superclass method.

3. An abstract class is not instantiated itself but serves as a superclass for other classes.

4. You can write a super statement that calls a superclass constructor but only in the subclass's constructor.

5. In an inheritance relationship, the subclass constructor always executes before the superclass constructor.

6. Because the subclass is more specialized than the superclass, it is sometimes necessary for the subclass to replace inadequate superclass methods with more suitable ones.

7. When a subclass overrides a superclass method, only the subclass's version of the method can be called with a subclass object.

8. Inheritance involves a subclass, which is the general class, and a superclass, which is the specialized class.

9. It is not possible for a superclass to call a subclass's method.

10. When a subclass extends a superclass, the public members of the superclass become public members of the subclass.

11. If two methods in the same class have the same name but different signatures, the second overrides the first.

12. Every class has a toString method and an equals method inherited from the Object class.

13. All methods in an abstract class must also be declared abstract.

14. A compiler error will result if an anonymous inner class tries to use a variable that is not final, or not effectively final.

15. A functional interface is simply an interface that has one abstract method.

MULTIPLE CHOICE

1. A __________ member's access is somewhere between public and private.

2. Which of the following shows the inheritance relationships among classes in a manner similar to that of a family tree?

3. In Java, a reference variable is __________ because it can reference objects of types different from its own, as long as those types are related to its type through inheritance.

4. A(n) __________ method is a method that appears in a superclass but expects to be overridden in a subclass.

5. If a subclass constructor does not explicitly call a superclass constructor, __________.

6. Which of the following is true about protected access?

7. All fields declared in an interface __________.

8. If a class contains an abstract method __________.

9. In an inheritance relationship __________.

10. __________ is a special type of expression used to create an object that implements a functional interface.

11. What is required for an interface method that has a body?

12. __________ tells the Java compiler that a method is meant to override a method in the superclass.

13. The __________ key word is used to call a superclass constructor explicitly.

14. Which of the following is an example of a lambda expression?

15. What type of relationship exists between two objects when one object is a specialized version of another object?

16. A subclass can directly access __________.

17. When an "is a" relationship exists between objects, the specialized object has __________.

18. If you don't provide an access specifier for a class member, the class member is given __________ access by default.

19. A protected member of a class may be directly accessed by __________.

20. All methods specified by an interface are __________.

21. If a method in a subclass has the same signature as a method in the superclass, the subclass method __________ the superclass method.

22. In __________, inheritance is shown with a line that has an open arrowhead at one end that points to the superclass.

23. In a class hierarchy __________.

24. A subclass may call an overridden superclass method by __________.

25. Which key word indicates that a class inherits from another class?

26. When a method is declared with the __________ modifier, it cannot be overridden in a subclass.

27. Which of the following is the operator used to determine whether an object is an instance of a particular class?

28. A class becomes abstract when you place the __________ key word in the class definition.

29. Protected class members can be denoted in a UML diagram with the __________ symbol.

30. Which of the following statements declares Salaried as a subclass of PayType?

31. If ClassC is derived from ClassB which is derived from ClassA, this would be an example of

32. Which of the following statements correctly specifies two interfaces?

33. In the following statement, which is the superclass?

public class ClassA extends ClassB implements ClassC

34. In the following statement, which is the subclass?

public class ClassA extends ClassB implements ClassC

35. In the following statement, which is the interface?

public class ClassA extends ClassB implements ClassC

36. What is wrong with the following code?

public class ClassB extends ClassA

{

public ClassB()

{

int init = 10;

super(40);

}

}

37. In the following code, what will the call to super do?

public class ClassB extends ClassA

{

public ClassB()

{

super(40);

System.out.println("This is the last statement "+

"in the constructor.");

}

}

38. In the following code, which line has an error?

Line 1 public interface Interface1

Line 2 {

Line 3 int FIELDA = 55;

Line 4 public int methodA(double){}

Line 5 }

39. In the following code, which line in ClassA has an error?

Line 1 public interface MyInterface

Line 2 {

Line 3 int FIELDA = 55;

Line 4 public int methodA(double);

Line 5 }

Line 6 public class ClassA implements MyInterface

Line 7 {

Line 8 FIELDA = 60;

Line 9 public int methodA(double) { }

Line 10 }

40. In the following code, which line will cause a compiler error?

Line 1 public class ClassA

Line 2 {

Line 3 public ClassA() {}

Line 4 public int method1(int a){}

Line 5 public final int method2(double b){}

Line 6 }

Line 7 public ClassB extends ClassA

Line 8 {

Line 9 public ClassB(){}

Line 10 public int method1(int b){}

Line 11 public int method2(double c){}

Line 12 }

41. Given the following code:

Line 1 public class ClassA

Line 2 {

Line 3 public ClassA() {}

Line 4 public void method1(int a){}

Line 5 }

Line 6 public class ClassB extends ClassA

Line 7 {

Line 8 public ClassB(){}

Line 9 public void method1(){}

Line 10 }

Line 11 public class ClassC extends ClassB

Line 12 {

Line 13 public ClassC(){}

Line 14 public void method1(){}

Line 15 }

Which method will be executed when the following statements are executed?

ClassC item1 = new ClassA();

item1.method1();

42. Given the following code:

Line 1 public class ClassA

Line 2 {

Line 3 public ClassA() {}

Line 4 public void method1(int a){}

Line 5 }

Line 6 public class ClassB extends ClassA

Line 7 {

Line 8 public ClassB(){}

Line 9 public void method1(){}

Line 10 }

Line 11 public class ClassC extends ClassB

Line 12 {

Line 13 public ClassC(){}

Line 14 public void method1(){}

Line 15 }

Which method1 will be executed when the following statements are executed?

ClassA item1 = new ClassB();

item1.method1();

43. In the following code, what is missing from ClassA?

Line 1 public interface MyInterface

Line 2 {

Line 3 int FIELDA = 55;

Line 4 public int methodA(double);

Line 5 }

Line 6 public class ClassA implements MyInterface

Line 7 {

Line 8 FIELDA = 60;

Line 9 public int methodB(double) { }

Line 10 }

44. Given the following code, which statement is true?

public class ClassB implements ClassA{ }

45. If a subclass constructor does not explicitly call a superclass constructor __________.

46. Replacing inadequate superclass methods with more suitable subclass methods is known as __________.

47. If two methods have the same name but different signatures they are __________.

48. When a subclass overloads a superclass method __________.

49. When declaring class data members it is best to declare them as __________.