Egckb-Java-2 - Martin 5

Front 1

Call the addItem method of the client object. What must be included in the statement?

Back 1

client.addItem(); the parenthesis must be included

Front 2

If you want to format a string before output, what method of the System could you use?

Back 2

System.out.format();

Front 3

What could a method return? (3)

Back 3

1) reference to an obj; 2) a primitive; 3) null;

Front 4

If a method returns an object, you can call the methods of that returned object in the ________ ________, using ________ method calls.

Back 4

same statement; nested

Front 5

Why would you use a class method?

Back 5

creating a general utility function which might need to be independent of object instances, but makes sense to include in the class

Front 6

What is an object reference?

Back 6

an address indicating where an object is stored

Front 7

What are primitive type wrappers?

Back 7

classes, whos objects can contain primitive values

Front 8

What is Autoboxing?

Back 8

automatic conversion of primitives to their respective object wrappers and vice versa

Front 9

What is unboxing?

Back 9

conversion of primitive type object wrappers to their primitive values

Front 10

What is Casting?

Back 10

Converting one type to another

Front 11

How does the == operator behave with objects?

Back 11

it determine whether both sides of the operator refer to the same object

Front 12

What method of a String object, could you call to perform a comparison?

Back 12

String.equals()

Front 13

How do you define a constant?

Back 13

use the keyword final before the declaration i.e. final string name = Tom;

Front 14

What does System.out.println(x) do

Back 14

Prints to the system console the value of x followed by a line break

Front 15

What does System.out.print(x) do

Back 15

Prints to the system console, the value of x without a line break

Front 16

List three kinds of comments in Java

Back 16

single line (//) with no ending tag, multi-line (/*) with an ending tag (*/) and Javadoc (/**) with an ending tag (*/)

Front 17

What is special about comments that start with (/**) and ends with (*/)

Back 17

javadoc comments; are designed to be read by utilities which can create external documentation

Front 18

What is a literal?

Back 18

any number, text, or other value

Front 19

In the following expression, pennyTotal = pennyTotal + 4L; What does the L after 4L indicate?

Back 19

It formats the number 4 (a literal value) as the data type long

Front 20

How would you use a literal with octal numbering? for the octal number 777

Back 20

Add a zero in front of the number, 0777

Front 21

How would you use a literal with hexidecimal numbers? for the number FF?

Back 21

Prepend 0x (zero-x), 0xFF

Front 22

How would you use a literal with binary numbers? for the number 11111111?

Back 22

Prepend with 0b (zero-b), 0b11111111

Front 23

All floating-point literals are considered to be of the type _________. How would you assign a literal value to a float var? for 3.1415927?

Back 23

double, the literal followed by an F, like this: 3.1415927F

Front 24

How can you use exponents in floating-point literals? for the number 12 to the power of 22?

Back 24

use e or E to denote the exponent, 12e22 or 12E22

Front 25

You can not use commas in large numbers like 3,500,000 as a literal. What else can you do to ensure readability?

Back 25

In Java 7 and higher, use underscores like 3_500_000

Front 26

T/F? Only the literals 1 or 0 may be assigned to a boolean in Java.

Back 26

False, you can only assign the literals true or false to boolean in Java

Front 27

How are character (char) literals expressed?

Back 27

using single quotes

Front 28

Identify the character escape code: \n

Back 28

New line

Front 29

Identify the character escape code: \t

Back 29

Tab

Front 30

Identify the character escape code: \b

Back 30

Backspace

Front 31

Identify the character escape code: \r

Back 31

Carriage return

Front 32

Identify the character escape code: \f

Back 32

Formfeed

Front 33

Identify the character escape code: \\

Back 33

Backslash (the 1st backslash denotes an escape character)

Front 34

To use a single or double quote in a literal, what must you do?

Back 34

Prefix it with an escape code - backslash \

Front 35

Most mathematical operators can be safely used on integers, except ...

Back 35

division. the result may end up being a floating-point number and that can not be handled by an int

Front 36

What is the safest way to determine data types for numbers to be used in calculations?

Back 36

by examining the type youre trying to end up with. using incompatible types will result in unpredictable values

Front 37

Increment var x

Back 37

x++;

Front 38

Decrement var x

Back 38

x--;

Front 39

In the following expression, where y=1; x = y++; What value is x assigned?

Back 39

1

Front 40

In the following expression, where y=1; x = ++y; What value is x assigned?

Back 40

2

Front 41

What is the difference between prefix and postfix operators, when assigning to a variable (++x x--)

Back 41

prefix (++x) performs the operation, then makes the assignment; postfix (x++) performs assignment, then performs the operation

Front 42

The difference between & and &&

Back 42

AND operator; 1) &, the expression on both sides of the operator are evaluated; 2) &&, if the left expression is false, the right expression is never evaluated

Front 43

The difference between | and ||

Back 43

OR operator; 1) |, both sides of the operator are evaluated; 2) ||, if the left side is true, the right side is never evaluated

Front 44

What is the ^ comparison operator?

Back 44

XOR, if left or right side of operator are opposites, expression is true. If both are same, expression is false.

Front 45

What is special about the String data type in Java?

Back 45

1) allows direct assignment of data; 2) treated as a class not a data type; 3) creates an instance of the class when assigned to

Front 46

Are primitive data types in Java, also objects?

Back 46

No

Front 47

Use the ___ keyword to create an instance of a class. Provide an example.

Back 47

new; Object objectName = new Object();

Front 48

What are the default delimiters in StringTokenizer?

Back 48

spaces, tabs, newlines, cr or ff

Front 49

At a high level, what happens when you create a new instance?

Back 49

1) memory is allocated for it; 2) constructor is called

Front 50

What is a constructor?

Back 50

special method that initializes a new object

Front 51

When a class has multiple constructors, how are they differentiated from each other?

Back 51

number and type of arguments (also called its signature)

Front 52

What is Java garbage collection?

Back 52

Java can determine whether an object has any live references to it. It periodically checks for unused objects, disposes of them and reclaims the memory.