Chapter 16

Question 1

Java collections framework contain other ______ generic data-structures

Answer 1

Prebuilt

Question 2

Examples of collections

Answer 2

Contacts list, music playlist, members of sport teams

Question 3

What do iterators do

Answer 3

Walk through collections

Question 4

A collection is a _____ ______ (actually an object) that can hold references to other objects

Answer 4

Data structure

Question 5

Usually collections contain references to objects of any type that has the ______ ___________ (inheritance, composition is a has-a relationship) with the collection’s element type. The collections-framework interfaces declare the operations to be performed generically on various types of collections.

Answer 5

Is-a relationship

Question 6

Interface Collection is the ______ __________ in the collections hierarchy from which interfaces Set, Queue and List are derived.

Answer 6

Root interface

Question 7

The collections-framework classes and interfaces are members of package ________

Answer 7

Java.util

Question 8

As a result, the Object references obtained from a collection needed to be ________ to an appropriate type to allow the program to process the objects correctly. __________ should be avoided

Answer 8

Downcast

Question 9

Wrapper classes

Answer 9

Boolean, Byte, Character, Double, Float, Integer, long and short

Question 10

T/F
Wrapper classes are final classes so you can’t extend them. Primitive types do not have methods, so the methods related to a primitive type are located in the corresponding type-wrapper class

Answer 10

T

Question 11

takes primitives (int, double, Boolean, float, etc) and turn them into reference (Double, Integer, etc) types (generic classes/containers require reference classes).

converts a primitive type to an object of the corresponding type-wrapper class (reference type). Performed automatically

Answer 11

Boxing

Question 12

Our of reference into primitive type

Answer 12

Unboxing

Question 13

What are proper generic classes

Answer 13

ArrayList, LinkedList, Iterator, Map, Set

Question 14

___________ is the same as an array, but it is dynamic/mutable (resizable).

Answer 14

ArrayList

Question 15

T/F the List interface is implemented by ArrayList and LinkedList

Answer 15

True

Question 16

List [name] = new ArrayList<>();

Answer 16

T

Question 17

a collection that associates keys to values and cannot contain duplicate keys. _____ does NOT derive from Collection.

Answer 17

Map

Question 18

a collection that does not contain duplicates

Answer 18

Set

Question 19

an ordered collection that can contain duplicate elements.

Answer 19

List

Question 20

Methods such as sort, reverse, addAll, shuffle etc are from

Answer 20

Static class collections (contains bulk operations)

Question 21

What does method Add() do from class List

Answer 21

adds elements to the end of the List

Question 22

From List

appends all elements of one list to another. Example: list1.addAll(list2); sets list2 to null.

Answer 22

AddAll

Question 23

From List

Prints list contents

Answer 23

printList

Question 24

Iterator uses

Answer 24

When you want to change the contents (for loop goes through contents)

Question 25

At runtime, behavior occurs based on what is received. Common example is with Inheritance

Answer 25

Polymorphic

Question 26

assumption) example “l = []” knows it is a list, whatever is in the list determines the type. In generic classes and methods
Or: Map m = new HashMap();

Answer 26

Type inferencing