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Listing 5 - Question 5.
/*File Q05.java ************************************************//* Integer and Double are both subclasses ofNumber. Both classes define a method named doubleValue that returns the encapsulatednumeric value as type double. Both classes also contain a method named intValue thatreturns the encapsulated numeric value as type int.*/ public class Q05{public static void main(String[] args){Foo<Integer>iFoo = new Foo<Integer>(15); System.out.println(iFoo.get().intValue());displayClass(iFoo); }//end main//-------------------------------------------// static void displayClass(Foo<Number>obj){ System.out.println(obj.getClass());}//end displayClass }//end class Q05//=============================================// class Foo<T extends Number>{ private T obj;public Foo(T obj){ this.obj = obj;}//end constructor public T get(){return obj; }//end get}//end Foo //=============================================//
Figure 5 - Question 5.
15 class Foo

Answer 5

Question 6

True or False: The code shown in Listing 6 will compile and run successfully producing the output shown in Figure 6 .

Listing 6 - Question 6.
/*File Q06.java ************************************************/import java.awt.Frame; import javax.swing.JInternalFrame;import java.awt.Container; /*Frame and JInternalFrame are both subclasses of Container. Both classes define a constructorthat accepts a String as a title. Both classes define a method named getTitle that returns thetitle string. */public class Q06{ public static void main(String[]args){ Foo<Frame>fFoo = new Foo<Frame>( new Frame("Frame title"));System.out.println(fFoo.get().getTitle()); displayClass(fFoo);}//end main //-------------------------------------------//static void displayClass(Foo<Container>obj){ System.out.println(obj.getClass());}//end displayClass }//end class Q06//=============================================// class Foo<T extends Container>{ private T obj;public Foo(T obj){ this.obj = obj;}//end constructor public T get(){return obj; }//end get}//end Foo //=============================================//
Figure 6 - Question 6.
Frame title class Foo

Answer 6

Figures

Listings

What is the meaning of the following two images?

These images were inserted here simply to insert some space between the questions and the answers to keep them from being visible on the screen at thesame time.

Spacer image of a rabbit and a penguin.

This image was also inserted for the purpose of inserting space between the questions and the answers.

Spacer image of a penguin and some houses.

Answers

Answer 6

False. This program illustrates that you cannot pass an object of a parameterized class to a method that is designed to accept an incoming parameterof that class with a specific type of parameter that is a superclass of the actual type of parameter. An attempt to compile the program results in the errorshown in Figure 7 .

Figure 7 - Answer 6.
Q06.java:29: error: method displayClass in class Q06 cannot be applied to given types;displayClass(fFoo); ^required: Foo<Container>found: Foo<Frame>reason: actual argument Foo<Frame>cannot be converted to Foo<Container>by method invocation conversion 1 error

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Answer 5

False. This program illustrates that you cannot pass an object of a parameterized class to a method that is designed to accept an incoming parameterof that class with a specific type of parameter that is a superclass of the actual type of parameter. An attempt to compile the program results in the errorshown in Figure 8 .

Figure 8 - Answer 5.
Q05.java:23: error: method displayClass in class Q05 cannot be applied to given types;displayClass(iFoo); ^required: Foo<Number>found: Foo<Integer>reason: actual argument Foo<Integer>cannot be converted to Foo<Number>by method invocation conversion 1 error

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Answer 4

True. This program illustrates passing an object of a parameterized class to a method that is designed to accept an incoming parameter of that class witha specific type of parameter.

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Answer 3

True. This program illustrates passing an object of a parameterized class to a method that is designed to accept an incoming parameter of that class with aspecific type of parameter.

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Answer 2

True. This program illustrates the successful use of bounded type parameters.

Back to Question 2

Answer 1

True. This program illustrates the successful use of bounded type parameters. It also illustrates the use ofautoboxing to encapsulate primitive types int and double into objects of the wrapper classesInteger and Double.

Back to Question 1

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java4250r: Review of Generics, Inheritance, and Subtypes
  • File: Java4250r.htm
  • Published: 10/20/13
Disclaimers:

Financial : Although the Connexions site makes it possible for you to download aPDF file for this module at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, youshould be aware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version ofthe module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale onAmazon.com showing me as the author. I neither receive compensation for those sales nor do I know who does receive compensation. If youpurchase such a book, please be aware that it is a copy of a module that is freely available on cnx.org and that it was made andpublished without my prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.

-end-

Questions & Answers

a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
how did I we'll learn this
Noor Reply
f(x)= 2|x+5| find f(-6)
Prince Reply
f(n)= 2n + 1
Samantha Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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