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Figure 6 - Question 11.

Answer 11

Question 12

Design and write a class named A12Box which, when used in conjunction with the code shown in Listing 7 , will compile and run successfully producing the output shown in Figure 7 .

Listing 7 - Question 12.
/*File Q12.java ************************************************/public class Q12{public static void main(String[] args){A12Box<String,Integer>boxA = new A12Box<>("abcde",new Integer(500)); System.out.println(boxA.get1());System.out.println(boxA.get2());A12Box<Integer,String>boxB = new A12Box<>(new Integer(900),"fghijkl"); System.out.println(boxB.get1());System.out.println(boxB.get2()); }//end main}//end class Q12 //=============================================//
Figure 7 - Question 12.
abcde 500900 fghijkl

Answer 12

Question 13

Given: When mixing legacy code with generic code, you may encounter messages similar to those shown in Figure 8 .

Figure 8 - Question 13.
Note: Example.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.

True or False: In such cases, the term "unchecked" means that the compiler does not have enough type information to perform all type checks necessary to ensure type safety.

Answer 13



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.


Answer 13


Back to Question 13

Answer 12

One possible solution is provided in Listing 8 below.

Listing 8 - Answer 12.
/*File A12Box.java ************************************************/public class A12Box<T1,T2>{ private T1 t1;private T2 t2; public A12Box(T1 t1,T2 t2){this.t1 = t1; this.t2 = t2;}//end constructorpublic T1 get1(){ return t1;}//end get1public T2 get2(){ return t2;}//end get2 }//end A12Box//=============================================//

Back to Question 12

Answer 11

One possible solution is provided in Listing 9 below.

Listing 9 - Answer 11.
/*File A11Box.java ************************************************/public class A11Box<T>{ private T t;public A11Box(T t){ this.t = t;}//end constructorpublic T get(){ return t;}//end get }//end A11Box//=============================================//

Back to Question 11

Answer 10


Back to Question 10

Answer 9

False. This program produces the error message shown in Figure 9 below.

Figure 9 - Answer 9.
Q09.java:8: error: illegal start of type Box<>box = new Box<Integer>(); ^1 error

Back to Question 9

Answer 8

One possible solution is shown in Listing 10 below.

Listing 10 - Answer 8.
/*File A08Box.java ************************************************/public class A08Box<T>{ private T t;public void set(T t){ this.t = t;}//end setpublic T get(){ return t;}//end get }//end A08Box//=============================================//

Back to Question 8

Answer 7

False. This program produces the compiler errors shown in Figure 10 below.

Figure 10 - Answer 7.
Q07.java:8: error: type Box does not take parameters Box<Integer>box = new Box<Integer>(); ^Q07.java:8: error: type Box does not take parameters Box<Integer>box = new Box<Integer>(); ^2 errors

Back to Question 7

Answer 6


Back to Question 6

Answer 5


Back to Question 5

Answer 4


Back to Question 4

Answer 3

False. The correct statement is:

"Type parameters provide a way for you to re-use the same code with different inputs. The inputs to type parameters are types ."

Back to Question 3

Answer 2


Back to Question 2

Answer 1

False. The correct statement is

"Generics add stability to your code by making more of your bugs detectable at compile time ."

Back to Question 1


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java4220r: Review of Generic Types
  • File: Java4220r.htm
  • Published: 09/02/13

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.


Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
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
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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