is an application of abstraction and protects the behaviors of an object from being modified by users.
is a requirement of Java. A class won’t compile unless all fields are declared private.
is an application of abstraction and protects against object users gaining direct access to object state.
is an application of security and protects against hackers modifying and corrupting our code.
2. A class method such as addMonthlyBonus(double x) that receives an input parameter and uses it to change the instance variable of an object is called a
constructor
default constructor
accessor method
mutator method
3. Select all of the following method definitions below that employ the correct syntax to define a constructor for the class Vehicle. A partial list of the class instance variables includes:
int year;
double odometer;
...
public Vehicle(){
}
public void Vehicle(double mileage){
odometer = mileage;
}
public makeVehicle(int year){
this.year = year;
}
public Vehicle(double mileage, int year){
this(mileage);
this.year = year;
}
public Vehicle(double odometer, int year){
odometer = odometer;
year = year;
}
4. When a constructor is written for the class (select all that apply)
the object was updated when the return statement was executed.
5. Consider the code
Pet sparky = new Pet();
Pet fido = sparky;
Line 2 of this code…
creates a new object named sparky with the same state data found in fido.
creates a new object named fido with the same state data found in sparky.
sets the object fido to reference or “point to” the object sparky.
compares the object fido do the object sparky and returns true or false.
6. Select all of the scenarios where using a static class constant would be appropriate.
To declare a constant that is used in different methods of the class and whose value never changes.
To declare a constant that is somehow associated with the class and may be accessed by client programs.
To declare a variable that is used in different methods of the class. This helps to avoid having to pass and return it as a parameter.
To share the state of that variable across many different objects of the class, like a count variable to keep track of how many objects have been created.
These are answers for Java for Android Week 3
Module 7 quiz on inheritance
1. Consider a class Student whose state includes name and age, Joanne who is a Student, and PartTime whose state includes all of the fields of Student and also maximumHours.
Student is a _____________________
Joanne is a _________________________
PartTime is a ____________________
sub class
Student object
super class
super class
client
subclass
super class
Student object
inherited class
super class
Student object
subclass
2. When creating a subclass
only write the methods that are public.
write both the inherited and the additional state and behavior of the subclass.
only write the instance variables and methods that are added to the subclass.
only write the instance variables and methods that are inherited by the subclass.
3. Why do we aim to minimize the amount of code we have to write by not repeating code segments within a Java project?
It facilitates code reuse. An object that contains all of its state and behavior in a single file is “portable” and can be included in many different Java projects.
It makes projects unique. An object that contains all of its state and behavior in a single file is not easily reused.
It makes debugging easier. Implementation details that only appear once in a project can be corrected or improved by editing in only one place.
It makes a program run faster.
It improves readability, code is easier to trace when implementation details are found in only on location.
