Section 3 Generics and collection
(Answer
all questions in this section)
1. A generic
class is a type of class that associates one or more non-specific Java types
with it. The types are determined when an object of that class is created.
True or false? Mark
for Review
True
(*)
False
2. Which of
the following are true about a Type Interface Diamond?
(Choose
all correct answers)
It
allows you to create a generic method as you would an ordinary method, without
specifying a type between angle brackets. (*)
It is
represented by the angle brackets <>. (*)
It is
an extension of the Collections class that creates a list.
It is a
keyword in Java that prints a diamond to the console screen.
None of
the above.
3. Choose
the instance where it would be preferable to use a collection without generics. Mark for Review
When
you have a List.
When
the Java type doesn't matter.
When
you wish to use the collection for more than one Java type.
When
you already know the Java type that the collection will hold. (*)
4. Collections
are used with generics when you already know what type you will be collecting
and you are only collecting that one type.
True or false? Mark
for Review
True
False
(*)
5. Which of
the following are true about Lists?
Mark for Review
They
grow and shrink as you add and remove objects.
They
maintain a specific order.
They
allow duplicates.
They
extend Collections.
All of
the above. (*)
6. ArrayList
is a Collection that already exists in Java and is very similar to an array.
True or false? Mark
for Review
True
(*)
False
7. Which of
these could be a set? Why? Mark for
Review
{1, 1,
2, 22, 305, 26} because a set may contain duplicates and all its elements are
of the same type.
{"Apple",
1, "Carrot", 2} because it records the index of the elements with
following integers.
{1, 2,
5, 178, 259} because it contains no duplicates and all its elements are of the
same type. (*)
All of
the above are sets because they are collections that can be made to fit any of
the choices.
8. A HashMap
is initialized with a KeyType and a ValueType inside angle brackets.
True or false? Mark
for Review
True
(*)
False
9. Which of
the following are true about deque?
Mark for Review
It is
pronounced "deck" for short.
It
implements a stack.
Allows
for insertion or deletion of elements from the first element added or the last
one
All of
the above. (*)
10. What is
the correct definition of Enumeration (or enum)? Mark for Review
A list
of elements that is dynamically stored.
A Double-Ended
Queue.
A
keyword that specifies a class whose objects are defined inside the class. (*)
Code
that initializes a HashSet.
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