4209233
Descripción
Test por bowtietigers, actualizado hace más de 1 año
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Creado por bowtietigers
hace casi 9 años
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Pregunta 1
Pregunta
Which of the following choices might serve as an interface for the other choices listed?
Respuesta
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Piano
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Drum
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Guitar
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Instrument
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FrenchHorn
Pregunta 2
Pregunta
Which of the following code segments causes a compile-time error?
Respuesta
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Airplane boeing707 = new Airplane();
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Flier boeing707 = new Flier();
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Flier boeing707 = new Airplane();
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Airplane boeing707 = new Airplane(); Flier airTraveler = boeing707;
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Airplane boeing707 = new Airplane(); Flier airTraveler; airTraveler = (Airplane) beoing707;
Pregunta 3
Pregunta
Consider the following code segment.
1 Airplane skyRider = new Airplane();
2 Flier skyRider2 = skyRider;
3 Athlete skyRider3 = (Athlete) skyRider2;
4 Airplane skyRider4 = (Airplane) skyRider2;
5 Flier skyRider5 = skyRider4;
Which statement above will cause a run-time error and throw an exception?
Respuesta
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Statement 1
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Statement 2
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Statement 3
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Statement 4
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Statement 5
Pregunta 4
Pregunta
Airplane c = new Airplane();
Flier f = new Airplane();
Athlete a = new SkiJumper("Ann", "Smith");
SkiJumper s = new SkiJumper("John", "Doe");
Which of the following statements is not legal?
Respuesta
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c.fly();
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f.fly();
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a.train(3);
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s.train(3);
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a.fly();
Pregunta 5
Pregunta
Airplane c = new Airplane();
Flier f = new Airplane();
Athlete a = new SkiJumper("Ann", "Smith");
SkiJumper s = new SkiJumper("John", "Doe");
Which of the following statements needs a cast?
I. f = c;
II. a = s;
III. s = a;
Respuesta
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I only
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II only
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III only
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I and II only
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I and III only
Pregunta 6
Pregunta
Suppose class C implements an interface I by implementing all of the methods of I and no further methods. Then which of the following must be true?
Respuesta
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All instance variables or C are public.
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All methods of C are abstract.
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All methods of C are public.
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All constants of C are public.
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All instance variables of C are private.
Pregunta 7
Pregunta
Which of the following statements is true about casting?
Respuesta
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You must cast to convert from an interface type to a class type.
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You must cast to convert from a class type to an interface type.
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You cannot cast to convert an interface type to a class type.
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You cannot cast from a class type to an interface type.
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Both a and b above are true.
Pregunta 8
Pregunta
Which of the following statements is true about dynamic binding?
Respuesta
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Dynamic binding occurs during compile time.
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Dynamic binding occurs when the appropriate overloaded method is selected.
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Dynamic binding is another name for early binding.
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In dynamic binding, the virtual machine selects the appropriate method.
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Dynamic binding occurs only when an interface declares public static final constants.
Pregunta 9
Pregunta
Which of the following statements about interfaces is not true?
Respuesta
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An interface can specify constants that can be used by all classes that implement the interface.
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An interface can specify variables that can be used by all classes that implement the interface.
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An interface can specify methods that must be defined by all classes that implement the interface.
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An interface name cannot be instantiated.
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The interface contains declarations but not implementations.
Pregunta 10
Pregunta
Suppose foo is an object of class C, and C implements the interface type I. Which of the following statements must be true?
Respuesta
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foo was constructed with the constructor of I.
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C assigns values to all constants declared in the interface I.
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C supplies an implementation for all methods of the interface I.
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foo must be declared as I foo = new C();
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All methods of I are declared as private.
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