<< Chapter < Page Chapter >> Page >

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

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
hmm well what is the answer
how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
is it a question of log
I rally confuse this number And equations too I need exactly help
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
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?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
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
how do you translate this in Algebraic Expressions
linda 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
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
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
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!

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
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?