4.9 Java4050r: review  (Page 2/2)

Answer 8

Question 9

True or False? In Listing 1 , a method named add is called to populate the TreeSet collection and the ArrayList collection with the same values in the same order.

Answer 9

Question 10

True or False? Given that in Listing 1 , a method named add is called to populate the TreeSet collection and the ArrayList collection with the same values in the same order, the two collections end up containing the same values

Answer 10

Question 11

True or False? Given that in Listing 1 , the TreeSet object filters out duplicate values, the TreeSet object and the ArrayList object end up containing all of the other values in the same order.

Answer 11

Question 12

True or False? In Listing 1 , the fillIt method receives an incoming parameter that is a reference to a collection object. The fillIt method calls the add method on the incoming reference several times in succession to add elements to the collection, being careful to satisfy thespecial requirements of the type of collection object.

Answer 12

Question 13

True or False? In Listing 1 , the fillIt method calls the same method name ( add ) on each of the collection objects. (They are physically different methods with the same name.) . The behavior of one add method is different from the behavior of the other add method. In both cases, the behavior is appropriate for the underlying data structure. The actual type of the underlyingdata structure isn't known to the fillIt method.

Answer 13

Question 14

True or False? The inheritance structure of the core collection interfaces in the Java Collections Framework is shown below. Indentation is used to indicatethe parent-child relationships among the interfaces.

• Collection
  • Set
    • SortedSet
  • List
  • Queue
  • Deque
• Map
  • SortedMap

Answer 14

Question 15

True or False? Every class that implements an interface in the tree rooted in Collection is required to support all of the methods (operations) declared in the Collection interface.

Answer 15

Listings

• Listing 1 . Program named Ap401.

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.

This image was also inserted for the purpose of inserting space between the questions and the answers.

Answers

Answer 15

False. Every class that implements an interface in the tree rooted in Collection is not required to support all of the methods (operations) declared in the Collection interface.

Rather, some of the methods in the Collection interface are designated as "optional operation" in the documentation.

If a given implementation doesn't support a specific method, it must throw an UnsupportedOperationException . The author of the implementation is responsible for providing documentation that identifies the optional operationsthat the implementation does and does not support.

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Answer 14

True.

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Answer 13

True.

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Answer 12

False. In Listing 1 , the fillIt method receives an incoming parameter that is a reference to a collection object. The fillIt method calls the add method on the incoming reference several times in succession to add elements to the collection, without regard for the actual typeor underlying implementation of the collection object. (As written, the fillIt method has no way of knowing the actual type or underlying implementation of the collection object.)

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Answer 11

False. By implementing the SortedSet interface, the TreeSet object is required to present its contents to an iterator in ascending natural order. The ArrayList object is not subject to such a contract. Therefore, the TreeSet object presents its contents to the iterator as 1234 (with no duplicate elements) while the ArrayList object presents its contents to the iterator as 44321, which is the same orderthat the values were added to the object.

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Answer 10

False. The TreeSet class implements the SortedSet interface. SortedSet is a sub interface of Set . One of the characteristics of a Set object is that it doesn't allow duplicate elements. The ArrayList class is not subject to such a contract. Therefore, the ArrayList object ends up containing duplicate copies of the value 4 while the TreeSet object ends up with no duplicates.

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Answer 9

True.

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Answer 8

False. Given that both the TreeSet class and the ArrayList class inherit an abstract method named add from the Collection interface, each class is required to define a concrete version of the add method but those two methods are not required to exhibit the same behavior. The behavior of the add method for each class should be appropriate for the type of object instantiatedfrom the class.

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Answer 7

True.

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Answer 6

False. Both the TreeSet class and the ArrayList class implement the Collection interface.

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Answer 5

True.

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Answer 4

True.

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Answer 3

False. There is more than one way to implement a list. Two common ways involve arrays and linked structures.

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Answer 2

True.

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Answer 1

1234 44321

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Miscellaneous

This section contains a variety of miscellaneous information.

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