Java Ch10
Java ch10
- 1.10.1 Q1: Polymorphism enables you to:
- A.
A. program in the general.
- B.
B. program in the specific.
- C.
C. absorb attributes and behavior from previous classes.
- D.
D. hide information from the user. d. hide information from the user.
- 2.10.1 Q2: Which of the following statements about interfaces is false?
- A.
A. An interface describes a set of methods that can be called on an object, providing a default implementation for the methods.
- B.
B. An interface describes a set of methods that can be called on an object, not providing concrete implementation for the methods.
- C.
C. Interfaces are useful when attempting to assign common functionality to possibly unrelated classes.
- D.
D. Once a class implements an interface, all objects of that class have an is-a relationship with the interface type.
- 3.10.2 Q1: For which of the following would polymorphism not provide a clean solution?
- A.
A. A billing program where there is a variety of client types that are billed with different fee structures.
- B.
B. A maintenance log program where data for a variety of types of machines is collected and maintenance schedules are produced for each machine based on the data collected.
- C.
C. A program to compute a 5% savings account interest for a variety of clients.
- D.
D. An IRS program that maintains information on a variety of taxpayers and determines who to audit based on criteria for classes of taxpayers.
- 4.10.2 Q2: Polymorphism allows for specifics to be dealt with during:
- A.
A. execution.
- B.
B. compilation.
- C.
C. programming.
- D.
D. debugging.
- 5.10.3 Q1: Which statement best describes the relationship between superclass and subclass types?
- A.
A. A subclass reference cannot be assigned to a superclass variable and a superclass reference cannot be assigned to a subclass variable.
- B.
B. A subclass reference can be assigned to a superclass variable and a superclass reference can be assigned to a subclass variable.
- C.
C. A superclass reference can be assigned to a subclass variable, but a subclass reference cannot be assigned to a superclass variable.
- D.
D. A subclass reference can be assigned to a superclass variable, but a superclass reference cannot be assigned to a subclass variable.
- 6.10.4 Q1: A(n) class cannot be instantiated.
- A.
A. final.
- B.
B. concrete.
- C.
C. abstract.
- D.
D. polymorphic.
- 7.10.4 Q2: Non-abstract classes are called:
- A.
A. real classes.
- B.
B. instance classes.
- C.
C. implementable classes.
- D.
D. concrete classes.
- 8.10.5 Q1: It is a UML convention to denote the name of an abstract class in:
- A.
A. bold.
- B.
B. italics.
- C.
C. a diamond.
- D.
D. there is no convention of the UML to denote abstract classes—they are listed just as any other class.
- 9.10.5 Q2: If the superclass contains only abstract method declarations, the superclass is used for:
- A.
A. implementation inheritance.
- B.
B. interface inheritance.
- C.
C. Both. d. Neither.
- D.
C. Both.
- 10.10.5.1 Q1: Which of the following could be used to declare abstract method method1 in abstract class Class1 (method1 returns an int and takes no arguments)?
- A.
A. public int method1();
- B.
B. public int abstract method1();
- C.
C. public abstract int method1();
- D.
D. public int nonfinal method1();
- 11.10.5.1 Q2: Which of the following statements about abstract superclasses is true?
- A.
A. abstract superclasses may contain data.
- B.
B. abstract superclasses may not contain implementations of methods.
- C.
C. abstract superclasses must declare all methods as abstract.
- D.
D. abstract superclasses must declare all data members not given values as abstract.
- 12.Consider the abstract superclass below:public abstract class Foo{ private int a; public int b; public Foo( int aVal, int bVal ) { a = aVal; b = bVal; } // end Foo constructor public abstract int calculate();} // end class FooAny concrete subclass that extends class Foo:
- A.
A. Must implement a method called calculate.
- B.
B. Will not be able to access the instance variable a.
- C.
C. Neither (a) nor (b).
- D.
D. Both (a) and (b)
- 13.10.5.5 Q1: Consider classes A, B and C, where A is an abstract superclass, B is a concrete class that inherits from A and C is a concrete class that inherits from B. Class A declares abstract method originalMethod, implemented in class B. Which of the following statements is true of class C?
- A.
A. Method originalMethod cannot be overridden in class C—once it has been implemented in concrete class B, it is implicitly final.
- B.
B. Method originalMethod must be overridden in class C, or a syntax error will occur.
- C.
C. If method originalMethod is not overridden in class C but is called by an object of class C, an error occurs.
- D.
D. None of the above.
- 14.10.5.6 Q1: When a superclass variable refers to a subclass object and a method is called on that object, the proper implementation is determined at execution time. What is the process of determining the correct method to call?
- A.
A. execution time binding.
- B.
B. execution binding.
- C.
C. just-in-time binding.
- D.
D. late binding.
- 15.10.5.6 Q2: Every object in Java knows its own class and can access this information through method .
- A.
A. getClass.
- B.
B. getInformation.
- C.
C. objectClass.
- D.
D. objectInformation.
- 16.10.5.7 Q1: Assigning a subclass reference to a superclass variable is safe:
- A.
A. because the subclass object has an object of its superclass.
- B.
B. because the subclass object is an object of its superclass.
- C.
C. only when the superclass is abstract.
- D.
D. only when the superclass is concrete.
- 17.10.6 Q1: Classes and methods are declared final for all but the following reasons:
- A.
A. final methods allow inlining the code.
- B.
B. final methods and classes prevent further inheritance.
- C.
C. final methods are static.
- D.
D. final methods can improve performance.
- 18.10.6 Q2: All of the following methods are implicitly final except:
- A.
A. a method in an abstract class.
- B.
B. a private method.
- C.
C. a method declared in a final class.
- D.
D. static method.
- 19.10.6 Q3: Declaring a method final means:
- A.
A. it will prepare the object for garbage collection.
- B.
B. it cannot be accessed from outside its class.
- C.
C. it cannot be overloaded.
- D.
D. it cannot be overridden.
- 20.10.7 Q1: An interface may contain:
- A.
A. private static data and public abstract methods.
- B.
B. only public abstract methods.
- C.
C. public static final data and public abstract methods.
- D.
D. private static data and public final methods.
- 21.Which of the following does not complete the sentence correctly?An interface .
- A.
A. forces classes that implement it to declare all the interface methods.
- B.
B. can be used in place of an abstract class when there is no default implementation to inherit.
- C.
C. is declared in a file by itself and is saved in a file with the same name as the interface followed by the .java extension.
- D.
D. can be instantiated.
- 22.10.7.1 Q1: The UML distinguishes an interface from other classes by placing the word “interface” in above the interface name.
- A.
A. italics.
- B.
B. carets.
- C.
C. guillemets.
- D.
D. bold.
- 23.10.7.2 Q1: Interfaces can have methods.
- A.
0
- B.
1
- C.
2
- D.
D. any number of
- 24.10.7.3 Q1: Which keyword is used to specify that a class will define the methods of an interface?
- A.
A. uses.
- B.
B. implements.
- C.
C. defines.
- D.
D. extends.
- 25.10.7.3 Q2: Which of the following is not possible?
- A.
A. A class that implements two interfaces.
- B.
B. A class that inherits from two classes.
- C.
C. A class that inherits from one class, and implements an interface.
- D.
D. All of the above are possible.
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