Which of the following is NOT one of the 3 main categories of collections? In other words, which of these objects does not, itself, represent a collection of items?

Iterator

List

Map

Set

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Question 21 pts

Which of the following is true about Lists and Sets?

Lists are indexed; Sets are not.

Lists may contain duplicate items; Sets do not.

Both of the above.

None of the above.

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Question 31 pts

Which of the following may be used to examine every item in the List myList?

Option A:

for( int i = 0; i < myList.size( ); i++ )  System.out.println( myList.get( i ) ); 

Option B:

for( String s : myList )  System.out.println( s ); 

Option C:

Iterator it = myList.iterator( );  while( it.hasNext( ) )  System.out.println( it.next( ) );

Option A only.

Option B only.

Option C only.

Either A or B, but not C.

Any of the above.

None of the above.

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Question 41 pts

Which of the following may be used to examine every item in the Set mySet?

Option A:

for( int i = 0; i < mySet.size( ); i++ )  System.out.println( mySet.get( i ) ); 

Option B:

for( String s : mySet )  System.out.println( s ); 

Option C:

Iterator it = mySet.iterator( );  while( it.hasNext( ) )  System.out.println( it.next( ) );

Option A only.

Option B only.

Option C only.

Either B or C, but not A.

A, B or C may be used.

None of the above.

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Question 51 pts

Every key in a Map must be unique. What happens when a Map receives a 'put' message specifying a key that is already used in the Map?

A DuplicateKeyException is thrown.

The map entry for the key is updated -- its associated value is replaced by the new value specified, and the old value is returned by the 'put' method.

The map entry for the key is updated -- its associated value is replaced by the new value specified, and null is returned by the 'put' method.

The map entry for the key is updated -- the new value specified is added to the list of values associated with the key.

No change is made to the Map, and the 'put' method returns null.

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Question 61 pts

Which of the following could be an "expensive" operation (an operation that takes a long time to complete) in an ArrayList?

adding a new item at the end of the list when size( ) is less than capacity

adding a new item at the beginning of the list

using get(itemNumber) to examine a list item in the middle of the list

iterating through the list

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Question 71 pts

Which of the following could be an "expensive" operation in the SimpleLinkedList class we discussed?

adding a new item at the end of the list

adding a new item at the beginning of the list

using get(itemNumber) to examine a list item in the middle of the list

calling 'next()' using an iterator provided by the list

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Question 81 pts

What will be the contents of myList, in the correct order, after the following sequence of operations? (Assume all operations are supported by the list implementation used.)

List myList = ... // create new, empty list  myList.add( "red" );  myList.add( "green" );  myList.add( "red" );  myList.add( 1, "black" );

[ "red", "green", "red", "black" ]

[ "black", "green", "red" ]

[ "red", "black", "green", "red" ]

[ "black", "red", "green" ]

[ "red", "black", "red" ]

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Question 91 pts

What will be the contents of mySet, regardless of order, after the following sequence of operations? (Assume all operations are supported by the set implementation used.)

Set mySet = ... // create new, empty set  mySet.add( "red" );  mySet.add( "green" );  mySet.add( "red" );  mySet.add( "black" );

[ "red", "green", "red", "black" ]

[ "black", "green", "red" ]

[ "green", "red" ]

[ "black" ]

[ "green", "black" ]

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Question 101 pts

What will be the contents of myMap, regardless of order, after the following sequence of operations? (Assume all operations are supported by the map implementation used.) Answers are shown as key=value pairs.

Map myMap = ... // create new, empty map  myMap.put( "red", "green" );  myMap.put( "orange", "blue" );  myMap.put( "red", "yellow" );  myMap.put( "blue", "black" );

[ "red"="green", "orange"="blue", "red"="yellow", "blue"="black" ]

[ "orange"="blue", "red"="yellow" ]

[ "red"="green", "orange"="blue" ]

[ "red"="yellow", "blue"="black" ]

[ "orange"="blue", "red"="yellow", "blue"="black" ]