16. Inheritance Flashcards
What two steps are needed to delete an element in a partially filled array?
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What is UML short for?
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In the representation for a class, how are public items distinguished from private ones?
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What four values are used to generate a colour?
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If the relationship ‘A is a B’ is modelled by two classes A and B, which is the superclass and which is the subclass?
A is a subclass B is a superclass
How do we invoke the constructor of the superclass, and when?
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When do we invoke the constructor of the superclass implicitly?
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What kinds of method can be overridden? Can the new version have a different body? Different parameters? Different name?
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What simple errors is the @Override annotation protect us from?
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If an object is polymorphic, what does that mean? And how do we achieve it?
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In what sense might a method be dynamically bound? Which types of method have this feature?
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In what way does a subclass extend its superclass?
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How do we make a class abstract, and what can we not do with it when we have made it abstract?
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How do we define an abstract method, and when do we? In what sense do we not override an abstract method?
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What does it mean to make a method final, and how do we achieve it? What kinds of method can be made final? What about a final class?
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How do we create an extension of a class which has more state?
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How is the idea of adding more instance methods related to adding more object state?
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How do we determine if an object is an instance of a particular class?
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What is the essential difference between a class cast and primitive type cast?
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Which of the following models ‘is a’ and which models ‘has a’?
1.
public class DieselTrain extends Train {
}
- public class Train {
private Carriage[] carriages;
}
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When might we want to use an overridden method, and how do we?
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What is the purpose of constructor chaining?
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When do we invoke another constructor from the same class, and how?
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What exactly is a default constructor, and when do we get one?
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All classes, except Object, have something. What is that thing?
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What does this default Object: toString() produce?
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Assuming a point class defined as one might expect, what is the affect of the following code?
System.out.println(new Point(10, 20));
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