EXAM

Question 1

An interface is a class that includes:

Answer 1

Abstract public methods and constant values

Question 2

Interfaces hold values by default how?

Answer 2

Public, static, final

Question 3

What are the two main uses of interfaces in Java?

Answer 3

1) Implementing a common function throughout many classes

2) Simulate multiple inheritance

Question 4

What keyword is used when a class uses an interface?

Answer 4

implements

Question 5

If a method has a code block in an interface, what keyword is used?

Answer 5

default

Question 6

Do you have to override a default method from an interface?

Answer 6

No

Question 7

What kind of inheritance does Java use?

Answer 7

Single inheritance

Question 8

Can you instantiate an object of an interface class?

Answer 8

No

Question 9

What is a functional interface?

Answer 9

An interface with only one abstract method

Question 10

What is an exception?

Answer 10

An object that signals an error

Question 11

What is a major benefit of using exceptions for errors?

Answer 11

Separates the code for errors from the code while running smoothly

Question 12

Why should exceptions only be used for unusual or catastrophic events?

Answer 12

Exceptions involve a lot of overhead, potentially reducing performance dramatically.

Question 13

What does a catch block use as a parameter?

Answer 13

An exception object

Question 14

What are the 4 categories of exceptions?

Answer 14

1) Code or Data Errors
2) Standard Method Exceptions
3) Throwing your own exceptions
4) Java errors

Question 15

What are all exceptions a subclass of?

Answer 15

Throwable

Question 16

What are the 2 subclasses of Throwable?

Answer 16

1) Error

2) Exception

Question 17

Unchecked exceptions are from which class?

Answer 17

The Runtime Class (Error class too)

Question 18

What are some common runtime exceptions?

Answer 18

ArithmeticException, IndexOutOfBounds, NullPointer

Question 19

What are the 2 ways to deal with checked exceptions?

Answer 19

1) Confess using “throws” keyword in header

2) try-catch blocks

Question 20

What block of code is always executed regardless of exceptions?

Answer 20

finally block

Question 21

What is important to remember when writing multiple catch blocks?

Answer 21

Order matters. The most abstract (least specific) should be at the bottom.

Question 22

What are 3 useful methods held in Throwable class?

Answer 22

getMessage()
printStackTrace()
printStackTrace(printStream e)

Question 23

When defining your own exception class, what class must be a superclass?

Answer 23

Throwable

Question 24

What is the best class to extend your own exception classes from?

Answer 24

Exception

Question 25

What kind of programs are GUIs?

Answer 25

Event-Driven Programs

Question 26

What is meant by “heavyweight” when referirng to GUI?

Answer 26

Depend heavily on OS

Question 27

What did Swing improve upon from the original Java AWT GUI components?

Answer 27

Lightweight (less OS involvement), more powerful

Question 28

What is AWT?

Answer 28

Abstract Windows Toolkit

Question 29

What is a container object?

Answer 29

An object to hold other GUI components

Question 30

What are 3 examples of container objects?

Answer 30

1) Window
2) Frame
3) Panel

Question 31

How do you set a JFrame’s position in the middle?

Answer 31

setLocationRelativeTo(null);

Question 32

Which container comes with a title?

Answer 32

JFrame

Question 33

What should be the final method in your boilerplate code?

Answer 33

setVisible(true)

Question 34

What is the most common layout manager?

Answer 34

FlowLayout

Question 35

What is the default layout manager for JFrame?

Answer 35

BorderLayout

Question 36

What is the Event Delegation Model?

Answer 36

The responsibility for handling events is given to an object other than the one that produced the event

Question 37

What is an event?

Answer 37

An object created when a user interacts with something, like a button in a GUI

Question 38

What kind of event does a JButton create?

Answer 38

ActionEvent

Question 39

What is the mother of all classes in JavaFX?

Answer 39

Application Class

Question 40

What is the top level container class in JavaFX?

Answer 40

Stage Class

Question 41

Which class in JavaFX is analogous to a JFrame in Swing?

Answer 41

Stage class

Question 42

Which sub-container typically gets added to a stage container?

Answer 42

Scene

Question 43

What method provides the Stage object?

Answer 43

launch()

Question 44

What code is needed in main to start a GUI in JavaFX?

Answer 44

launch()

Question 45

What are individual elements like TextFields and Buttons called in JavaFX?

Answer 45

Nodes

Question 46

What is a node without a child called?

Answer 46

Terminal node (or leaves)

Question 47

What is a scene graph?

Answer 47

The collection of all the nodes

Question 48

What is a root node?

Answer 48

The top-level node

Question 49

What are the 3 life-cycle methods provided by the application class?

Answer 49

1. init()
2. start()
3. stop()

Question 50

What method is analogous to the JFrame constructor method in JavaFx?

Answer 50

start(Stage primaryStage)

Question 51

What are the two types of MouseEvent listeners?

Answer 51

1. MouseListener

2. MouseMotionListener

Question 52

What are 3 different kinds of event objects?

Answer 52

ActionEvent, ChangeEvent, ItemEvent