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Answer 13

Listings

What is the meaning of the following two images?

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Answers

Answer 13

True.

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Answer 12

False. Such an object can contain duplicate values but cannot contain duplicate keys .

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Answer 11

False. A SortedMap is a Map that maintains its entries in ascending order, sorted according to the keys' natural ordering, or according to a Comparator provided at the time of the SortedMap creation.

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Answer 10

True, in the opinion of this author.

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Answer 9

True.

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Answer 8

False. The natural ordering of a collection of objects of a given class is determined by the code written into the concrete compareTo method when the compareTo method inherited from the Comparable interface is defined. Objects instantiated from a class that doesn't implement the Comparable interface don't have a natural ordering.

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Answer 7

False. The natural ordering of the elements in a collection is the ordering imposed by the objects' own compareTo method.

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Answer 6

True.

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Answer 5

True.

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Answer 4

The program output is the three lines of text shown below (without the bullets) .

  • Joe Bill Tom JOE BILL TOM
  • TOM BILL JOE Tom Bill Joe
  • Tom TOM Joe JOE Bill BILL

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Answer 3

True.

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Answer 2

False? While it is true that the reverse method of the Collections class reverses the order of the elements in a specified list, the method has a void return type.

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Answer 1

False. The reverseOrder method of the Collections class returns a reference to an object of the interface type Comparator .

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Complete program listing

Listing 1 . Comparator07.java .
//File Comparator07.java //Copyright 2001, R.G.Baldwinimport java.util.*; public class Comparator07{public static void main(String args[]){new Worker().doIt(); }//end main()}//end class Comparator07 class Worker{public void doIt(){ Iterator iter;Collection ref; ref = new ArrayList();Populator.fillIt(ref); iter = ref.iterator();while(iter.hasNext()){ System.out.print(iter.next() + " ");}//end while loop System.out.println();Collections.reverse((List)ref); iter = ref.iterator();while(iter.hasNext()){ System.out.print(iter.next() + " ");}//end while loop System.out.println();Comparator aComparator= Collections.reverseOrder(); Collections.sort((List)ref, aComparator);iter = ref.iterator(); while(iter.hasNext()){System.out.print(iter.next() + " "); }//end while loopSystem.out.println(); }//end doIt()}// end class Worker class Populator{public static void fillIt(Collection ref){ ref.add("Joe");ref.add("Bill"); ref.add("Tom");ref.add("JOE"); ref.add("BILL");ref.add("TOM"); }//end fillIt()}//end class Populator

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Java4140r: Review
  • File: Java4140r.htm
  • Published: 12/03/13
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.

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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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