Java Reference
In-Depth Information
EXERCISES
1.
Mark the following statements as true or false.
a.
The constructor of a subclass specifies a call to the constructor of the
superclass in the heading of the constructor's definition.
b.
The constructor of a subclass specifies a call to the constructor of the
superclass using the name of the class.
c.
A subclass must define a constructor.
d.
In Java, polymorphism is implemented using late binding.
2.
Draw a class hierarchy in which several classes are subclasses of a single
superclass.
Suppose that a
class
Employee
is derived from the
class
Person
(see
Example 8-8, in Chapter 8). Give examples of data and method members
that can be added to the
class
Employee
.
3.
Identify the superclass and the subclass in each of the following pairs of classes.
a.
4.
d.
BankAccount
,
SavingsAccount
e.
GradStudent
,
Student
f.
Dog
,
Animal
5.
Draw the inheritance hierarchy diagram that shows the inheritance relation-
ship between the classes
Person
,
Student
,
Employee
, and
Instructor
.
6.
Draw the inheritance hierarchy diagram that shows the inheritance relation-
ship between the classes
Vehicle
,
Car
,
Sedan
,
Truck
,
PickupTruck
,
Object
, and
Animal
.
7.
Consider the following statement:
public class
Dog
extends
Animal
{
Employee
,
Person
Vehicle
,
Truck
b.
Circle
,
Cylinder
c.
...
}
In this declaration, which class is the base class and which class is the derived class.
8.
Consider the following class definitions:
class
Circle
public class
Cylinder
extends
Circle
{
{
private double
radius;
private double
height;
public
Circle(
double
)
public
Cylinder()
{
{
}
}
public
Circle()
public
Cylinder(
double
,
double
)
{
{
}
}
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