21. Collections Flashcards
Although there are different kinds of collections, what particular convenience do they all have in common? (Collections API)
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Name four methods from the Collection interface? Which collections have these methods?
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What deficiency arguable exists in the use of interfaces as a means of contractual obligation?
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What features characterize a collection as being a list?
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What is the type parameter of a List used for?
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What order does Lists: List interface: iterator() present the elements in?
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If we have ArrayList al = new ArrayList(); what type is the object referenced by the variable al - is it ArrayList, List, Collection or Object?
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How is Lists: ArrayList collection implemented?
d
For which implementation of Lists will add(index) and remove(index) instance methods be slow, and for which will they be fast?
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How is LinkedList collection implemented?
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What features characterize a collection as being a map?
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What are the type parameters of a Map interface used for?
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How is the TreeMap collection implemented?
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Howis the HashMap collection implemented?
d
What features characterize a collection as being a set?
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What is the type parameter of a Set interface used for?
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What order does the Sets: Set interface: iterator() present the elements in?
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If we have HashSet hs = new HashSet(); what type is the object referenced by the variable hs - is it HashSet, Set, Collection or Object?
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How is the TreeSet collection implemented?
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What order does Sets: TreeSet: iterator() present the elements in?
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How is HashSet collection implemented?
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Name a generic class method that is provided in Collections class. What restrictions are placed on its List method argument?
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What two abstract methods does this have?
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What two stages are involved in this?
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What is data stored in at run time? What kinds of things might we want to do with such stored data?
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What is the consequence of clashes, and how is their occurrence minimized?
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Why is the data structure called OBT?
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For what circumstances is linked list better than using an array?
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What three instance methods does Integer have in order for it to behave properly in the collections classes?
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What is hashCode() used for, and what properties should it have?
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What properties must hashCode() have, and what property should it have? How can we achieve this?
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When should we use a for-each loop with collections?
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