collection and collections

Question 1

collection interface

Answer 1

Java standard install, a generic interface called Collection which identifies some common methods for interacting with such data structures

Question 2

collections class

Answer 2

Java standard install, classcalled Collectionswhich includes some potentially useful static methods that can interact with Collection-based objects

Question 3

7 of the Collection methods

Answer 3

boolean add(E newVal)
 void clear() 
boolean contains(Object ref)
boolean remove(Object ref)
int size() 
boolean isEmpty() 
Object[] toArray()

Question 4

3 classes that implement Collection

Answer 4

ArrayList, PriorityQueue, Stack

Question 5

PriorityQueue

Answer 5

removes the smallest item every time you call remove()

handy for printing things smallest to largest:System.out.println(myFloatPQ.remove())

Question 6

collection interface benefits:

Answer 6

> a method that should be able to operate on multiple objects

>you can write the method to take a reference to any object that implements that interface!

Question 7

collection interface cons:

Answer 7

Java allows you to access data structures in other ways as well
(less secure)

Question 8

methods that can take arraylists object’s reference

Answer 8

> ArrayList class implements List which extends Collection
> any method which can take either a List or a Collection as a parameter  (methods in collection do this)

Question 9

sort

Answer 9

Collections.sort(myList);

use our compareTomethod as the basis for sorting the list behind the scenes.

Question 10

min, max

Answer 10

could print the record of the students with the alphabetically smallest and largest name: System.out.println(“Min: “+Collections.min(myList));
System.out.println(“Max: “+Collections.max(myList));

our compareTomethod would be used as the basis for determining this behind the scenes

Question 11

shuffle

Answer 11

randomly shuffle our list

Collections.shuffle(arrayList);