Syntax/grammer

Question 1

Assignment Statement

Answer 1

::===

ex balance= nuBalance

Question 2

Message Statement

Answer 2

.([actual parameter]);

ex. myaccount.setBalance(1234)

Question 3

Return statement

Answer 3

::== return[];

ex. return balance;

Question 4

What does () mean?
ex. account();

Answer 4

“This”

ex This account.

Question 5

What is a class?

Answer 5

Template of an object (cookie cutter, press)

contains methods and variables.

Question 6

What is a variable?

Answer 6

Variable contains information

Question 7

What is a Method?

Answer 7

Perform actions, Allows classes to do things.

Question 8

primitives in Java:

Answer 8

byte (number, 1 byte)
    short (number, 2 bytes)
    int (number, 4 bytes)
    long (number, 8 bytes)
    float (float number, 4 bytes)
    double (float number, 8 bytes)
    char (a character, 2 bytes)
    boolean (true or false, 1 byte)

Question 9

To declare and assign a number

Answer 9

int myNumber;
myNumber = 5;
or
int myNumber = 5;

Question 10

To define a floating point number,

Answer 10

float f = (float) 4.5;

Question 11

syntax for chars

Answer 11

char c = ‘g’;

Question 12

ways to use a string

Answer 12

// Create a string with a constructor
String s1 = new String("Who let the dogs out?");
// Just using "" creates a string, so no need to write it the previous way.
String s2 = "Who who who who!";
// Java defined the operator + on strings
String s3 = s1 + s2;

Question 13

Boolean

Answer 13

boolean b = false;
b = true;

boolean toBe = false;
b = toBe || !toBe;
if (b) {
    System.out.println(toBe);
}

int children = 0;
b = children; // Will not work
if (children) { // Will not work
    // Will not work
}

Question 14

The Arithmetic Operators (5)

Answer 14

\+       additive operator (also used for 
        String concatenation)
-       subtraction operator
*       multiplication operator
/       division operator
%       remainder operator

Question 15

The Unary Operators(5)

Answer 15

\+       Unary plus operator; indicates 
        positive value (numbers are 
        positive without this, however)
-       Unary minus operator; negates
        an expression
\++      Increment operator; increments
        a value by 1
--      Decrement operator; decrements
        a value by 1
!       Logical complement operator; 
        inverts the value of a boolean

Question 16

The Equality and Relational Operators(6)

Answer 16

==      equal to
!=      not equal to
>       greater than
>=      greater than or equal to
<       less than
<=      less than or equal to

Question 17

The Conditional Operators(2)

Answer 17

&& Conditional-AND

|| Conditional-OR

Question 18

instanceof <—-what does it do?

Answer 18

The instanceof operator compares an object to a specified type

Question 19

Field declarations are composed of three components, in order?

Answer 19

Zero or more modifiers, such as public or private.
The field’s type.
The field’s name.

Question 20

Defining Methods

Answer 20

1 Modifiers—such as public, private, and others you will learn about later.
2 The return type—the data type of the value returned by the method, or void if the method does not return a value.
3 The method name—the rules for field names apply to method names as well, but the convention is a little different.
4 The parameter list in parenthesis—a comma-delimited list of input parameters, preceded by their data types, enclosed by parentheses, (). If there are no parameters, you must use empty parentheses.
5 An exception list—to be discussed later.
6 The method body, enclosed between braces—the method’s code, including the declaration of local variables, goes here.

Question 21

method Explanation “Public”

Answer 21

Specifies that the method is accessible from outside a class

Question 22

method Explanation “Static”

Answer 22

Specifies that the method is a class method that is to be executable.even though no class objects have been created.

Question 23

method Explanation “Void”

Answer 23

Specifies that the method does not return a value

Question 24

Create an object syntax

Answer 24

ex. Point originOne = new Point(23, 94);

Declaration: The code originOne are all variable declarations that associate a variable name with an object type.
Instantiation: The new keyword is a Java operator that creates the object.
Initialization: The new operator is followed by a call to a constructor, which initializes the new object.

Question 25

Constructor syntax

Answer 25

A class contains constructors that are invoked to create objects from the class blueprint. Constructor declarations look like method declarations—except that they use the name of the class and have no return type. For example, Bicycle has one constructor:

public Bicycle(int startCadence, int startSpeed, int startGear) {
    gear = startGear;
    cadence = startCadence;
    speed = startSpeed;
}

Question 26

WHat is an Accessor?

Answer 26

The methods that give other objects ac- cess to variables inside an object are called “accessors.”
ex:
1    public int getBalance() {
2
3}
4
5 public String getName() {
6 7}
return name;   // return the name

Question 27

Converting a String to an int

Answer 27

int guess= Integer.parseInt(stringGuess);

turns a number 2 into string “2”.

Question 28

Syntax for a cast Operator(change it from long to int)

Answer 28

long y = 42

int x = (int) y

Question 29

Name of pre build classes in Java

Answer 29

API or Java Library

Question 30

Arraylist: Adds the object parameter to the list

Answer 30

add(Object elem)

Question 31

Arraylist: removes the object at the index parameter

Answer 31

remove(int index)

Question 32

Arraylist: removes this object(if its in the arraylist).

Answer 32

remove(Object elem)

Question 33

Arraylist:returns “true” if theres a match for the object parameter

Answer 33

contains(Object elem)

Question 34

Arraylist: returns true if the list has no Elements

Answer 34

isEmpty()

Question 35

Arraylist:Returns either the index of the object parameter,or-1

Answer 35

indexOf(Object elem)

Question 36

Arraylist: Returns the number of elements currently in the list

Answer 36

size()

Question 37

Arraylist: Returns the object currently at the index parameter

Answer 37

get(in index)

Question 38

Define Arguments

Answer 38

Arguments are the things pass into the methods.
ex
d.bark(3)
3=argument/settings

Question 39

Define constructor

Answer 39

Constructor is an object with arguments in them. Must be the same as the class name it is in.
ex:
public class TUNA{
public TUNA(String Name){
girlname=name;}

main class
tuna tunaobject=new tuna(NAME)

Question 40

Rules for Getters and Setter

Answer 40

Mark instance variables private

Mark getters and setter public.

Question 41

What is a Instance Variable?

Answer 41

Instance Variable gets declared inside a class but not within a method.

Question 42

What is a local Variable?

Answer 42

Local variables are declared within a method.
LOCAL VARIABLES do Not get default values.
wrong = int b;
right= int b=12

Question 43

How do you save a file(4 steps)

Answer 43

1. Make a FileOutputStream
FileOutputStream fileStream = new FileOutputStream(“MyGame.ser”);

2.Make an ObjectOutputStream
ObjectOutputStream os = new ObjectOutputStream(fileStream);

3. Write the object
   os. writeObject(characterOne); os.writeObject(characterTwo); os.writeObject(characterThree);
4. Close the ObjectOutputStream
   os. close();

Question 44

What is overloading Method

Answer 44

Several methods same name different arguments

Question 45

Api for buttons

Answer 45

Import Javax.swing.*;

Question 46

API for listeners

Answer 46

java.awt.event.*;

Question 47

How do you read files.(5 steps)

Answer 47

1. Make a FileInputStream
FileInputStream fileStream = new FileInputStream(“MyGame.ser”);

2.Make an ObjectInputStream
ObjectInputStream os = new ObjectInputStream(fileStream);

3.read the objects
Object one = os.readObject(); Object two = os.readObject(); Object three = os.readObject();

4.Cast the objects
GameCharacter elf = (GameCharacter) one; GameCharacter troll = (GameCharacter) two; GameCharacter magician = (GameCharacter) three;

5. Close the ObjectInputStream
   os. close();