Question 1

In ________, inheritance is shown with a line that has an open arrowhead at one end that points to the superclass.
A) pseudocode
B) UML diagrams
C) CRC cards
D) hierarchy charts

Accepted Answer

UML diagrams use the notation of a line with an open arrowhead pointing to the superclass to represent inheritance. Pseudocode, CRC cards, and hierarchy charts do not typically use this notation for inheritance.

Question 2

You show inheritance in a UML diagram by connecting two classes with a line that has an open arrowhead that points to the subclass.

Accepted Answer

In UML diagrams, inheritance is shown by connecting two classes with a line that has an open arrowhead pointing to the superclass, not the subclass.

Question 3

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

Accepted Answer

This is true. To call a superclass constructor from a subclass, a super statement must be used, but it can only be called within the subclass's constructor.

Question 4

All methods specified by an interface are
A) private.
B) public.
C) protected.
D) static.

Accepted Answer

All methods specified by an interface are by default public, as an interface is used to provide a set of public methods that a class implementing it must define. Private, protected, and static methods are not allowed in an interface.

Question 5

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.

Accepted Answer

As the subclass is more specialized than the superclass, it may have unique needs or requirements that are not adequately met by the superclass methods. In such cases, it is necessary for the subclass to override or replace the inadequate superclass methods with more suitable ones.

Question 6

If a method in a subclass has the same signature as a method in the superclass, the subclass method ________ the superclass method.
A) inherits
B) overrides
C) overloads
D) implements

Accepted Answer

When a subclass method has the same signature as a method in the superclass, it is said to override the superclass method. This allows the subclass to provide its own implementation of the method, which may differ from the implementation provided by the superclass.

Question 7

Which of the following statements correctly specifies two interfaces?
A) public class ClassA implements [Interface1, Interface2]
B) public class ClassA implements (Interface1, Interface2)
C) public class ClassA implements Interface1 | Interface2
D) public class ClassA implements Interface1, Interface2

Accepted Answer

When specifying that a class implements an interface, multiple interfaces can be listed by separating them with commas, as in option D. Option A is close, but the square brackets suggest an array declaration rather than an interface implementation. Option B uses parentheses which are not valid in this context. Option C uses the bitwise OR operator which is also not valid in this context.

Question 8

In a UML diagram, you show a realization relationship by connecting a class and an interface with a
A) dashed line that has an open arrowhead at one end.
B) line that has an open diamond at one end.
C) dashed line.
D) line that has an open arrowhead at one end.

Accepted Answer

In UML, a realization relationship is depicted by a dashed line with an open arrowhead pointing towards the interface, indicating that the class implements the interface.

Question 9

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

Accepted Answer

This is a true statement. An abstract class is designed to be extended or subclassed by other classes, but cannot be instantiated on its own.

Question 10

When an "is a" relationship exists between objects, it means that the specialized object has all of the characteristics of the general object, plus additional characteristics that make it special.

Accepted Answer

This is the correct definition of an "is a" relationship in object-oriented programming.

Question 11

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

Accepted Answer

When a subclass overrides a superclass method, calling the method on a subclass object will execute the subclass's version of the method, not the superclass's version.

Question 12

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

Accepted Answer

Every class in Java directly or indirectly inherits from the Object class, and therefore inherits all of its members, including methods such as equals(), hashCode(), and toString().

Question 13

When a class implements an interface, an inheritance relationship known as ________ is established.
A) implemented heritage
B) interface inheritance
C) realized inheritance
D) abstract inheritance

Accepted Answer

When a class implements an interface, it inherits the interface's methods and must provide implementations for them. This is known as interface inheritance.

Question 14

A protected member of a class may be directly accessed by
A) methods of the same class.
B) methods of a subclass.
C) methods in the same package.
D) All of the above

Accepted Answer

A protected member can be accessed by any method within the same class, any subclass, and any class in the same package. Therefore, all the options provided in the question are correct.

Question 15

When a class contains an abstract method, you cannot create an instance of the class.

Accepted Answer

This is because the abstract method needs to be implemented by a subclass before an object can be created.

Question 16

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

Accepted Answer

In an inheritance relationship, the superclass constructor executes before the subclass constructor to ensure that the superclass is fully initialized before the subclass initialization begins.

Question 17

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

Accepted Answer

This is known as method overriding in object-oriented programming.

Question 18

In the following statement, which is the interface?
Public class ClassA extends ClassB implements ClassC
A) ClassA
B) ClassB
C) ClassC
D) ClassA, ClassB, and ClassC

Accepted Answer

The interface is ClassC, as it is being implemented by ClassA through the "implements" keyword. ClassB is being extended by ClassA, but it is not an interface. ClassA is the name of the class itself, and thus not considered an interface.

Question 19

Protected class members can be denoted in a UML diagram with the ________ symbol.
A) +
B) -
C) *
D) #

Accepted Answer

The "#" symbol is used to denote protected class members in a UML diagram. The other symbols represent different access modifiers: "+" for public, "-" for private, and "*" for package/protected (not commonly used).

Question 20

If ClassC is derived from ClassB, which is derived from ClassA, this would be an example of
A) a chain of inheritance.
B) linear inheritance.
C) multiple interfaces.
D) cascading classes.

Accepted Answer

ClassC inheriting from ClassB, which in turn inherits from ClassA creates a chain of inheritance. Each class inherits properties and methods from its parent class, building upon the previous class in the chain.

Quiz 9: Inheritance

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

You show inheritance in a UML diagram by connecting two classes with a line that has an open arrowhead that points to the subclass.

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

All methods specified by an interface are

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.

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

Which of the following statements correctly specifies two interfaces?

In a UML diagram, you show a realization relationship by connecting a class and an interface with a

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

When an "is a" relationship exists between objects, it means that the specialized object has all of the characteristics of the general object, plus additional characteristics that make it special.

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

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

When a class implements an interface, an inheritance relationship known as ________ is established.

A protected member of a class may be directly accessed by

When a class contains an abstract method, you cannot create an instance of the class.

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

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

In the following statement, which is the interface? Public class ClassA extends ClassB implements ClassC

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

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