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c) A
Map
can contain duplicate keys.
d) A
LinkedList
can contain duplicate values.
e)
Collections
is an
interface
.
f)
Iterator
s can remove elements.
g)
With hashing, as the load factor increases, the chance of collisions decreases.
h)
A
PriorityQueue
permits
null
elements.
Answers to Self-Review Exercises
16.1
a)
Iterator
. b) index. c) autoboxing. d)
ArrayList
,
Vector
. e) double. f) unmodifiable
wrapper. g) auto-unboxing. h)
disjoint
.
16.2
a) False. Autoboxing occurs when adding a primitive type to a collection, which means the
primitive type is converted to its corresponding type-wrapper class.
b)
False. A
Set
cannot contain duplicate values.
c)
False. A
Map
cannot contain duplicate keys.
d)
True.
e)
False.
Collections
is a
class
;
Collection
is an
interface
.
f)
True.
g)
False. As the load factor increases, fewer slots are available relative to the total number
of slots, so the chance of a collision increases.
h)
False. Attempting to insert a
null
element causes a
NullPointerException
.
Execises
16.3
Define each of the following terms:
a)
Collection
b)
Collections
c)
Comparator
d)
List
e) load factor
f) collision
g) space/time trade-off in hashing
h)
HashMap
16.4
Explain briefly the operation of each of the following methods of class
Vector
:
a)
add
b)
set
c)
remove
d)
removeAllElements
e)
removeElementAt
f)
firstElement
g)
lastElement
h)
contains
i)
indexOf
j)
size
k)
capacity
16.5
Explain why inserting additional elements into a
Vector
object whose current size is less
than its capacity is a relatively fast operation and why inserting additional elements into a
Vector
object whose current size is at capacity is a relatively slow operation.
16.6
By extending class
Vector
, Java's designers were able to create class
Stack
quickly. What are
the negative aspects of this use of inheritance, particularly for class
Stack
?
