4.7 Java4040r review  (Page 3/3)

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Answer 18

True.

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Answer 17

False. While implementation of the Set interface may have some minor impact on the searching speed of a TreeSet object, the primary reason for the fast searching speed is the fact that theimplementation uses a tree structure.

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Answer 16

True. A TreeSet object will perform the search very rapidly with a time cost of only log(n) where n is the number of elements. On the other hand,for the same number of elements, because of a different underlying data structure, a search on an ArrayList object will probably require more time than a search on a TreeSet object. As the number of elements increases, thedifference in time cost between the two will also increase.

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Answer 15

False. The Collection interface does not declare a method named get . Rather, the get method is added to the List interface to define a more specialized form of collection.

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Answer 14

False. While an ArrayList object may contain duplicate values, the ArrayList object in Listing 1 was populated with the values contained in the TreeSet object, which does not allow duplicate values. Therefore, in this case, the ArrayList object may not contain duplicate values.

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Answer 13

False. The code in Listing 1 instantiates an ArrayList object and populates it with the contents of the existing TreeSet object. As a result, we then have two different Collection objects of different actual types containing the same elements.

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Answer 12

True.

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Answer 11

True.

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Answer 10

False. The program shown in Listing 1 instantiates a TreeSet object and populates it with approximately 2,000,000 elements.

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Answer 9

True.

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Answer 8

False. The manner in which the search will be performed will probably differ from one concrete implementation of the interface to the next. For example, a TreeSet object will perform the search very rapidly with a time cost of only log(n) where n is the number of elements. On the other hand, for the same numberof elements, because of a different underlying data structure, a search on an ArrayList object will probably require more time than a search on a TreeSet object. As the number of elements increases, the difference in time cost between the two will also increase.

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Answer 7

True.

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Answer 6

False.

The contract for the contains method requires that the method:

• receives an incoming reference of type Object as a parameter
• searches the collection looking for an element that matches the incoming reference
• returns true if the collection on which the method is called contains the specified element and returns false otherwise.

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Answer 5

True.

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Answer 4

False. Iterator is not one of the concrete implementations.

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Answer 3

True.

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Answer 2

True.

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Answer 1

True.

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Miscellaneous

This section contains a variety of miscellaneous information.

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