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" The returned array will be "safe" in that no references to it are maintained by this collection. ... The caller is thus free to modify thereturned array."

Note, however, that there is still some danger that you need to be aware of, and you must use caution when using the contents of the array.

Back to Question 3

Answer 2

The program shown in Listing 1 produces the output shown in Figure 1 .

Figure 1 . Answer 2.
Collection contents B0 B1 L2 B3 B4 L5New array contents B0 B1 L2 B3 B4 L5Modified array contents XX B1 L2 B3 B4 L5Collection contents XX B1 L2 B3 B4 L5

Back to Question 2

Answer 1

True.

Back to Question 1

Complete program listing

Listing 1 . ToArray01.java.
//File ToArray01.java //Copyright 2001, R.G.Baldwinimport java.util.*; import javax.swing.*;public class ToArray01{ public static void main(String args[]){ new Worker().doIt();}//end main() }//end class ToArray01//===================================// class Worker{public void doIt(){ Collection ref;//Create, populate, and display the // contents of a collectionref = new LinkedList(); Populator.fillIt(ref);System.out.println("Collection contents"); showCollection(ref);//Get collection contents into the // array and display the new// contents of the array. Object[]array = ref.toArray(); System.out.println("New array contents");showArray(array); //Modify a property of an object// referred to by one of the // elements in the array. Display// array contents after // modificationSystem.out.println("Modified array contents"); ((JComponent)array[0]).setToolTipText("XX"); showArray(array);//Display the contents of the // collectionSystem.out.println("Collection contents"); showCollection(ref);}//end doIt() //-----------------------------------////Utility method for displaying // array contentsvoid showArray(Object[] array){for(int i = 0; i<array.length;i++){ if(array[i]== null){ System.out.print("null ");}else{ System.out.print(((JComponent)array[i]). getToolTipText() + " ");}//end else }//end for loopSystem.out.println(); }//end showArray()//-----------------------------------// //Utility method for displaying// collection contents void showCollection(Collection ref){Iterator iter = ref.iterator(); while(iter.hasNext()){System.out.print(((JComponent)iter.next()). getToolTipText() + " ");}//end while loop System.out.println();}//end showCollection }// end class Worker//===================================// class Populator{public static void fillIt(Collection ref){ ref.add(new JButton());ref.add(new JButton()); ref.add(new JLabel());ref.add(new JButton()); ref.add(new JButton());ref.add(new JLabel()); Iterator iter = ref.iterator();int cnt = 0; JComponent refVar;while(iter.hasNext()){ refVar = (JComponent)iter.next();if(refVar instanceof JButton){refVar.setToolTipText("B"+cnt++); }else{refVar.setToolTipText("L" + cnt++); }//end else}//end while loop }//end fillIt()}//end class Populator

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java4150r: Review
  • File: Java4150r.htm
  • Published: 12/04/13
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

the diagram of the digestive system
Assiatu Reply
allimentary cannel
Ogenrwot
How does twins formed
William Reply
They formed in two ways first when one sperm and one egg are splited by mitosis or two sperm and two eggs join together
Oluwatobi
what is genetics
Josephine Reply
Genetics is the study of heredity
Misack
how does twins formed?
Misack
What is manual
Hassan Reply
discuss biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles
Joseph Reply
what is biology
Yousuf Reply
the study of living organisms and their interactions with one another and their environments
AI-Robot
the study of living organisms and their interactions with one another and their environment.
Wine
discuss the biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles in an essay form
Joseph Reply
what is the blood cells
Shaker Reply
list any five characteristics of the blood cells
Shaker
lack electricity and its more savely than electronic microscope because its naturally by using of light
Abdullahi Reply
advantage of electronic microscope is easily and clearly while disadvantage is dangerous because its electronic. advantage of light microscope is savely and naturally by sun while disadvantage is not easily,means its not sharp and not clear
Abdullahi
cell theory state that every organisms composed of one or more cell,cell is the basic unit of life
Abdullahi
is like gone fail us
DENG
cells is the basic structure and functions of all living things
Ramadan
What is classification
ISCONT Reply
is organisms that are similar into groups called tara
Yamosa
in what situation (s) would be the use of a scanning electron microscope be ideal and why?
Kenna Reply
A scanning electron microscope (SEM) is ideal for situations requiring high-resolution imaging of surfaces. It is commonly used in materials science, biology, and geology to examine the topography and composition of samples at a nanoscale level. SEM is particularly useful for studying fine details,
Hilary
cell is the building block of life.
Condoleezza Reply
what is cell divisoin?
Aron Reply
Diversity of living thing
ISCONT
what is cell division
Aron Reply
Cell division is the process by which a single cell divides into two or more daughter cells. It is a fundamental process in all living organisms and is essential for growth, development, and reproduction. Cell division can occur through either mitosis or meiosis.
AI-Robot
What is life?
Allison Reply
life is defined as any system capable of performing functions such as eating, metabolizing,excreting,breathing,moving,Growing,reproducing,and responding to external stimuli.
Mohamed
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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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