Test 1 review

Question 1

abstract classes are used for…

Answer 1

setting up methods for subclasses

declaring private data fields

Question 2

abstract method

Answer 2

method that has no body

Question 3

can objects be created in abstract classes?

Answer 3

no

Question 4

what overrides abstract methods?

Answer 4

concrete methods

Question 5

how many interfaces can a class extend?

Answer 5

one

Question 6

how many interfaces can a class implement?

Answer 6

multiple

Question 7

interfaces contain

Answer 7

abstract methods

Question 8

what’s a type?

Answer 8

a collection of values

Question 9

simple type example

Answer 9

integer

Question 10

aggregate type example

Answer 10

bank account

Question 11

data item

Answer 11

piece of info drawn from a type

Question 12

what does a data structure do?

Answer 12

implement an ADT

Question 13

how does remove() work in a linked bag?

Answer 13

removes first item

Question 14

if node is in a package what must it define?

Answer 14

set and get methods

Question 15

removing the first node

Answer 15

set firstNode to reference the second node

decrement the number of entries

Question 16

removing a node that isn’t first

Answer 16

move the firstNode to the removed nodes spot
set firstNode to reference the second node
decrement the number of entries

Question 17

pros and cons of using arrays

Answer 17

pros:
adding and removing entries is fast
cons:
takes time to remove a SPECIFIC entry
takes time to copy entries when increasing size

Question 18

how are entries removed in arrays?

Answer 18

the last element becomes null and takes the spot of the removed element

Question 19

package

Answer 19

collection of classes

Question 20

pros and cons of using chains

Answer 20

pros:
flexible size
can remove and recycle nodes
adding entries to the beginning and end is simple
cons:
removing a specific entry requires searching
uses more memory than arrays

Question 21

scope of a variable

Answer 21

section of the code in which the variable is visible

Question 22

A class uses composition when it

Answer 22

declares an instance of another class as a data field

Question 23

abstraction

Answer 23

focus on what and not on how

Question 24

what can bags NOT do?

Answer 24

reorder items

Question 25

limitation of adding an item to a bag

Answer 25

you CANNOT specify where it goes

Question 26

cons of fixed arrays

Answer 26

wastes memory
limited capacity
cannot expand when full

Question 27

how does remove() work on fixed arrays?

Answer 27

it removes the last entry

Question 28

the first node is also called the

Answer 28

head reference

Question 29

access modifiers

Answer 29

public
private
protected

Question 30

what does “protected” mean?

Answer 30

accessible by the classes of the same package and the subclasses residing in any package

Question 31

is an interface a class?

Answer 31

NO