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Get and display the data in the container

Then the code in the next fragment uses the get method to get and display the values in each of the three elements, causing the followingtext to appear on the screen:

5 10 15

System.out.print(ref.get(0)+" "); System.out.print(ref.get(1)+" ");System.out.print(ref.get(2)+" ");

One step too far

Finally, the code in the next fragment goes one step too far and attempts to get a value from index 3, which is outside the bounds of the container.

System.out.print(ref.get(3)+" ");

This causes the get method of the container object to throw a NoSuchElementException . The program was not designed to handle this exception, so this causes the program to abort with the following text showing on thescreen:

5 10 15 java.util.NoSuchElementException at MyContainer.get(Ap154.java:49)at Worker.doIt(Ap154.java:30) at Ap154.main(Ap154.java:15)

(Note that the values of 5, 10, and 15 were displayed on the screen before the program aborted and displayed the error message.)

Back to Question 4

Answer 3

This program can produce either of the following depending on the value produced by a random boolean value generator:

  • B. Runtime Error
  • C. OK

Explanation 3

Throwing an exception

This program illustrates the use of the throw keyword to throw an exception.

(Note that the throw keyword is different from the throws keyword.)

Throw an exception if random boolean value is true

A random boolean value is obtained. If the value is true, the program throws an IllegalStateException and aborts with the following message on the screen:

java.lang.IllegalStateException at Worker.doIt(Ap153.java:29)at Ap153.main(Ap153.java:20)

If the random boolean value is false, the program runs to completion, displaying the text OK on the screen.

Instantiate a Random object

The following code fragment instantiates a new object of the Random class and stores the object's reference in a reference variable named ref .

void doIt(){ Random ref = new Random(new Date().getTime());

I'm not going to go into a lot of detail about the Random class. Suffice it to say that an object of this class provides methods that will return a pseudorandom sequence of values upon successive calls. You might think of this object as a random value generator.

Seeding the random generator

The constructor for the class accepts a long integer as the seed for the sequence.

(Two Random objects instantiated using the same seed will produce the same sequence of values.)

In this case, I obtained the time in milliseconds, relative to January 1, 1970, as a long integer, and provided that value as the seed. Thus, if you run the program two times in succession, with a time delay of at least one millisecondin between, the random sequences will be different.

Get a random boolean value

The code in the next fragment calls the nextBoolean method on the Random object to obtain a random boolean value. (Think of this as tossing a coin with true on one side and false on the other side.)

if(ref.nextBoolean()){ throw new IllegalStateException();

Throw an exception

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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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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