OOP Midterms

Question 1

Can be inherited but not instantiated

Answer 1

Abstract Class

Question 2

method only for abstract class, methods that don’t require implementation for its declaration.

Answer 2

Abstract Method

Question 3

All subclass should implement the abstract method

Answer 3

Method Signature

Question 4

If class is abstract have abstract method

Answer 4

Realization

Question 5

Cant be inherited but can instantiate

Answer 5

Final Class

Question 6

Cannot be override by connected classes

Answer 6

Final method

Question 7

Classes that implement an interface inherits only method signature

Answer 7

Interface Inheritance

Question 8

Key word used for implementing interface

Answer 8

“implements”

Question 9

Constant and prevents the reference from changing, vallue can be changed but not the size

Answer 9

Final Variable

Question 10

Object that groups multiple elements into a single unit

Answer 10

Java Collections

Question 11

Collection framework 3 elements

Answer 11

Interface
Implementations
Algorithms

Question 12

It is how you handle the collections

Answer 12

Interfaces

Question 13

The classes that actually hold the data

Answer 13

Implementations

Question 14

Useful routines

Answer 14

Algorithms

Question 15

Enforce type on the collection

Answer 15

Generics

Question 16

• stores elements in order added
• similar to array but growable
• allows to get and set using index
• fast in getting and setting elements
• slow in inserting and removing elements

Answer 16

List Collection

Question 17

• no duplicate
• maintain its order

Answer 17

Set collection

Question 18

Not sorted set

Answer 18

Hashset

Question 19

Sorted set

Answer 19

Treeset

Question 20

An object that map keys to values

Answer 20

Map Collection

Question 21

Not sorted map collection

Answer 21

Hashmap

Question 22

Sorted Map collection

Answer 22

Treemap

Question 23

was used to provide generic iteration for collection implementations

Answer 23

iterator

Question 24

How to determine class of an object

Answer 24

getClass()

Question 25

a nested class and it doesn’t need the reference of the outer class.

Answer 25

Static class

Question 26

there is only one copy of the variable in memory, regardless of how many instances of the class are created.

Answer 26

Static Variables

Question 27

used to check whether an object is an instance of a particular class or implements a particular interface.

Answer 27

InstanceOf

Question 28

allocates a memory location for the object and returns reference of the memory location

Answer 28

New Operator

Question 29

a number pointing to a memory location

Answer 29

Reference

Question 30

parameter passing

Answer 30

• pass-by-value
• pass-by-reference

Question 31

garbage collection
an object loses a reference when:

Answer 31

• reference goes out of scope
• reference is pointed to another object
• reference is pointed to null

Question 32

belongs to the class as a whole, not to a certain class

Answer 32

Static Members

use keyword: (static)