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Questions and Answers
A class diagram consists of a rectangle divided into three sections.
A class diagram consists of a rectangle divided into three sections.
True
When you use the method name with a child object, the parent's version of the method is used.
When you use the method name with a child object, the parent's version of the method is used.
False
When you create any subclass object, the subclass constructor must execute first, and then the superclass constructor executes.
When you create any subclass object, the subclass constructor must execute first, and then the superclass constructor executes.
False
A nonstatic method cannot override a static member of a parent class.
A nonstatic method cannot override a static member of a parent class.
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You cannot declare a class to be final.
You cannot declare a class to be final.
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In a UML diagram, an inheritance relationship is indicated with an arrow that points from the original class to the descendant class.
In a UML diagram, an inheritance relationship is indicated with an arrow that points from the original class to the descendant class.
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Subclasses are more specific than the superclass they extend.
Subclasses are more specific than the superclass they extend.
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It is useful to override the parent class members when the superclass data fields and methods are not completely appropriate for the subclass objects.
It is useful to override the parent class members when the superclass data fields and methods are not completely appropriate for the subclass objects.
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When a protected data field or method is created, it can be used within its own class or in any classes extended from that class; but it cannot be used by outside classes.
When a protected data field or method is created, it can be used within its own class or in any classes extended from that class; but it cannot be used by outside classes.
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An error is generated by the compiler when you attempt to override a static method with a nonstatic method.
An error is generated by the compiler when you attempt to override a static method with a nonstatic method.
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What is the mechanism that enables one class to acquire all the behaviors and attributes of another class?
What is the mechanism that enables one class to acquire all the behaviors and attributes of another class?
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When you create a class by making it inherit from another class, what does the new class automatically contain from the original class?
When you create a class by making it inherit from another class, what does the new class automatically contain from the original class?
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By convention, a class diagram contains what following each attribute or method?
By convention, a class diagram contains what following each attribute or method?
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Arrows used in a UML diagram to show inheritance relationships extend from where to where?
Arrows used in a UML diagram to show inheritance relationships extend from where to where?
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The ability to use inheritance in Java makes programs easier to write, _____, and more quickly understood.
The ability to use inheritance in Java makes programs easier to write, _____, and more quickly understood.
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The class used as a basis for inheritance is called what?
The class used as a basis for inheritance is called what?
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What keyword is used to achieve inheritance in Java?
What keyword is used to achieve inheritance in Java?
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Sometimes the superclass data fields and methods are not entirely appropriate for the subclass objects; in these cases, what do you want to do with the parent class members?
Sometimes the superclass data fields and methods are not entirely appropriate for the subclass objects; in these cases, what do you want to do with the parent class members?
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If a programming language does not support what, the language is not considered object-oriented?
If a programming language does not support what, the language is not considered object-oriented?
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_____ polymorphism is the ability of one method to work appropriately for subclasses of the same parent class.
_____ polymorphism is the ability of one method to work appropriately for subclasses of the same parent class.
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When you create parent and child classes of your own, the child classes use how many constructors?
When you create parent and child classes of your own, the child classes use how many constructors?
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When you create a class and do not provide a(n) _____, Java automatically supplies you with a default one.
When you create a class and do not provide a(n) _____, Java automatically supplies you with a default one.
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Usually, the subclass constructor only needs to initialize what that are specific to the subclass?
Usually, the subclass constructor only needs to initialize what that are specific to the subclass?
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You can use the keyword _____ within a method in a derived class to access an overridden method in a base class.
You can use the keyword _____ within a method in a derived class to access an overridden method in a base class.
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When you employ _____, your data can be altered only by the methods you choose and only in ways that you can control.
When you employ _____, your data can be altered only by the methods you choose and only in ways that you can control.
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Using the keyword _____ provides you with an intermediate level of security between public and private access.
Using the keyword _____ provides you with an intermediate level of security between public and private access.
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The methods in a subclass can use all of the data fields and methods belonging to its parent, with one exception: _____ members of the parent class are not accessible within a child class's methods.
The methods in a subclass can use all of the data fields and methods belonging to its parent, with one exception: _____ members of the parent class are not accessible within a child class's methods.
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If a _____ method has the same name as a parent class method and you use the name with a child class object, the child method hides the original.
If a _____ method has the same name as a parent class method and you use the name with a child class object, the child method hides the original.
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You can use the _____ modifier with methods when you don't want the method to be overridden.
You can use the _____ modifier with methods when you don't want the method to be overridden.
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You are never aware that _____ is taking place; the compiler chooses to use this procedure to save the overhead of calling a method.
You are never aware that _____ is taking place; the compiler chooses to use this procedure to save the overhead of calling a method.
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Which of the following statements will create a class named Red that is based on the class Color?
Which of the following statements will create a class named Red that is based on the class Color?
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Study Notes
Inheritance Concepts
- A class diagram features a rectangle divided into three sections to represent class structure.
- When interacting with subclass objects, the subclass's method version is executed, not the parent's.
- The execution sequence of constructors begins with the superclass constructor, followed by the subclass constructor.
- Nonstatic methods cannot override static members from parent classes, preserving method specificity.
- A class can indeed be declared as final, restricting further inheritance.
Unified Modeling Language (UML)
- UML diagrams use arrows to indicate inheritance relationships, pointing from the parent class (base class) to the child class (subclass).
- Class diagrams conventionally display the data type of each attribute or method after its name.
Advantages of Inheritance
- Inheritance helps reduce errors in Java programs, making them easier to write and understand.
- The base class serves as the foundation for new classes that inherit its characteristics and functions.
- Subclass constructors typically initialize fields unique to the subclass, promoting streamlined object construction.
Method Overriding and Super Keyword
- Overriding allows customization of parent class behaviors for better suitability to subclass contexts.
- The
superkeyword is used within a subclass to invoke methods from the parent class, ensuring original functionality can be accessed.
Access Modifiers and Data Hiding
- Protected members can be accessed within subclasses, while private members remain inaccessible in child classes.
- Information hiding ensures data integrity by restricting direct access, allowing only controlled modifications through designated methods.
Polymorphism and Method Hiding
- Polymorphism is essential for object-oriented programming, enabling methods to operate on subclasses of a common parent class.
- Static methods of subclasses can hide parent static methods if they share the same name.
- The
finalmodifier prevents method overriding, enforcing original method behavior.
Constructing Classes
- When no constructor is defined, Java provides a default constructor.
- There are three constructors involved when defining a child class, facilitating broader inheritance functionality.
Compiler Optimization
- Inlining refers to a compiler technique that optimizes method calls by integrating method code directly into callers, improving performance without developer awareness.
Studying That Suits You
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Description
Test your knowledge on the principles of inheritance in object-oriented programming through this quiz. Each flashcard presents statements about class diagrams, method usage, and constructor execution. See how well you understand these essential concepts in inheritance!
