Java Reference
In-Depth Information
11.24
Indicate true or false for the following statements:
Check
Point
You can always successfully cast an instance of a subclass to a superclass.
You can always successfully cast an instance of a superclass to a subclass.
11.25
For the GeometricObject and Circle classes in Listings 11.1 and 11.2, answer the
following questions:
a. Assume are circle and object created as follows:
Circle circle = new Circle( 1 );
GeometricObject object = new GeometricObject();
Are the following Boolean expressions true or false?
(circle instanceof GeometricObject)
(object instanceof GeometricObject)
(circle instanceof Circle)
(object instanceof Circle)
b. Can the following statements be compiled?
Circle circle = new Circle( 5 );
GeometricObject object = circle;
c. Can the following statements be compiled?
GeometricObject object = new GeometricObject();
Circle circle = (Circle)object;
11.26
Suppose that Fruit , Apple , Orange , GoldenDelicious , and McIntosh are
defined in the following inheritance hierarchy:
Fruit
Apple
Orange
GoldenDelicious
McIntosh
Assume that the following code is given:
Fruit fruit = new GoldenDelicious();
Orange orange = new Orange();
Answer the following questions:
a. Is fruit instanceof Fruit ?
b. Is fruit instanceof Orange ?
c. Is fruit instanceof Apple ?
d. Is fruit instanceof GoldenDelicious ?
e. Is fruit instanceof McIntosh ?
f.
Is orange instanceof Orange ?
 
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