GUI and Events

Question 1

How do you declare a generic class in java?

Answer 1

class myClass {
...
}

Question 2

How do you make wildcard extend a super type?

Answer 2

extends T>

Question 3

How do you make wildcard a supertype of a specific class?

Answer 3

super T>

Question 4

How do you implement selection sort?

Answer 4

1. repeat i times -> n
2. find the smallest element in the sub set {n, i - 1}
3. Move this element to position n

Question 5

What is the run time complexity of selection sort?

Answer 5

O(n^2)

Question 6

How do you implement insertion sort?

Answer 6

1. repeat i-1 times -> n
2. Itterate backwards through the sub set {0, n - 1} -> z
3. If the element z is greater than element n continue itterating
4. Otherwise, insert the element at position z + 1

Question 7

What is the runtime complexity of insertion sort?

Answer 7

O(n^2)

Question 8

How do you implement bubble sort?

Answer 8

1. Repeat i times -> n
2. repeat n - 1 times -> z
3. If element z is greater than element z + 1 swap the two elements

Question 9

What is the runtime complexity of buble sort?

Answer 9

O(n^2)

Question 10

What is the runtime complexity of merge sort?

Answer 10

O(n log n)

Question 11

How do you create a checked exception class?

Answer 11

make it extends Exception

Question 12

What is the superclass of unchecked exceptions?

Answer 12

Error

Question 13

How do you create a printwriter for a file?

Answer 13

File fName = new File(...);
PrintWriter myPrintWriter = new PrintWriter(fName);
myPrintWriter.println(...);

Question 14

What exception should be caught when opening files?

Answer 14

IOException

Question 15

How do you read data from an internet source?

Answer 15

URL url = new URL("www.mysite.com");
Scanner data = new Scanner(url.openStream());

Question 16

How do you create a new file reader in java

Answer 16

FileReader(File file) or

FileReader(String fileName)

Question 17

What exception should you handle when creating FileReader

Answer 17

FileNotFoundException

Question 18

What exception should be handled with PrintWriter

Answer 18

FileNotFoundException

Question 19

What exception occurs when there is an arithmetic error?

Answer 19

ArithmeticException

Question 20

What exception is thrown when an out of bound array location is accessed.

Answer 20

ArrayIndexOutOfBoundsException

Question 21

What exception is thrown when referencing a null object?

Answer 21

NullPointerException

Question 22

What exception occurs when out of bound string location is accessed?

Answer 22

StringIndexOutOfBoundsException

Question 23

What interface must event handlers implement?

Answer 23

EventHandler

Question 24

How do you use a lambda expression in java?

Answer 24

(param1…, paramn) -> action

Question 25

How do you create an anonymous inner class?

Answer 25

new myInterface() { // code};

Question 26

how do you get the button from mouse event?

Answer 26

getButton()

Question 27

How do you get the key character from a KeyEvent?

Answer 27

getKeyChar()

Question 28

How do you get the key code from a KeyEvent?

Answer 28

getKeyCode()

Question 29

How do you get a string desribing KeyCode

Answer 29

KeyEvent.getKeyText(int keyCode)

Question 30

How do you add a child to an element?

Answer 30

(element).getChildren.add(node)

Question 31

How do you add all nodes?

Answer 31

addAll(node1, node2, ...)

Question 32

How do you determine if a point is in a node javafx?

Answer 32

conatins(double localX, double localY)

Question 33

How do you get the id for a node?

Answer 33

getID()

Question 34

how do you display a stage?

Answer 34

show()

Question 35

what methods must be included in javaFX Applications

Answer 35

public void start(Stage primaryStage)

Question 36

How do you create a new scene

Answer 36

Scene myScene = new Scene(component, x, y)

Question 37

How do you get the source of an ActionEvent

Answer 37

getSource()

Question 38

How do you set on action button?

Answer 38

setOnAction

Question 39

What is a pane?

Answer 39

basic place to store components

Question 40

What is a Stack Pane?

Answer 40

Stacks components on top of eachother

Question 41

What is a flow pane?

Answer 41

Places row by row then overflows to next column or vise versa

Question 42

What is a border Pane

Answer 42

places nodes in specific regions

Question 43

What two methods must be implemented when using the setADT?

Answer 43

``` int size(); boolean add(T elt) ```

Question 44

How do you create an exception with a message?

Answer 44

Exception(String message)

Question 45

How do you get if iterator has next item?

Answer 45

hasNext()

Question 46

how do you get item form iterator?

Answer 46

next()

Question 47

how do you remove the current item in iterator?

Answer 47

remove()

Question 48

How do you preform an action on each remaining item in itterator?

Answer 48

forEachRemaining(Consumer super E> action)

Question 49

What does the iterable interface do?

Answer 49

It allows it to be used in a for each loop.

Question 50

How do you return the iterator element from an interable interface.

Answer 50

iterator()

Question 51

What methods must elements of hashSet override?

Answer 51

hashcode() and equals()

Question 52

What is the complexity of basic retrieval operations in treeSet?

Answer 52

o(n)

Question 53

What is the retrieval time for HashSet?

Answer 53

constant time

Question 54

What is the map interface header?

Answer 54

Interface Map K - Key type V - Type of mapped value

Question 55

how do you clear a map?

Answer 55

clear()

Question 56

How do you check if map contains key?

Answer 56

containsKey(Object key)

Question 57

How do you check if map contains value?

Answer 57

containsValue(Object value)

Question 58

How do you get an object by its key?

Answer 58

get(Object key)

Question 59

How do you returns the set of keys from a map?

Answer 59

keySet()

Question 60

how do you map an element to a specified key?

Answer 60

put(K key, V value)

Question 61

How do you add multiple elements to map?

Answer 61

putAll(Map extends K, extends V> m)

Question 62

How do you remove an object from map?

Answer 62

remove(Object key)

Question 63

How do you replace a key in a map?

Answer 63

replace(K key, V value)

Question 64

how do you get the size of a map?

Answer 64

size()

Question 65

What are the functions of a hashMap?

Answer 65

``` void get(Object key) void put(K key, V value) void remove(Object key) boolean remove(Object key, Object value) ```