Chapter 2

Question 1

What are Literals?

Answer 1

It is common for programs to include constants; in Java these are referred to as literals.
Ex: 123, 123.45, ’a’, ”Gosling”

Question 2

What are variables?

Answer 2

Variables is a named location in a computer’s memory, and the value stored in that location is controlled during the execution of programs.

Question 3

What are the two data types?

Answer 3

Primitive data types and data types defined via classes (objects)
Ex: String and System

Question 4

What are all the primitive data types?

Answer 4

Byte, short, int, long, float, double, char and Boolean

Question 5

What are Keywords?

Answer 5

Java reserves the use of certain names referred to as keywords.
Ex: int

Question 6

What are the Numeric Data types?

Answer 6

Numeric data types are used for numer values where there is no fractional component- all values are whole integers.
Ex: byte, short, int, long,

Question 7

What are operators?

Answer 7

They are calculations or actions that use a symbol.
Ex: +, -, /, %, *
All of these operators are binary operators, meaning that they have two operands. One operand is on the left side and the other on the right.

Question 8

What is arithmetic operation?

Answer 8

When the opera did of both are the same
Ex: int + int = int

Question 9

What does a Modulo do?

Answer 9

Modulo gives the remainder when the first operant is divided by the second operand.
Ex: 13%5 = 3

Question 10

How to use the long data type?

Answer 10

The value would have a suffix of L
Ex: 10025L

Question 11

What are operands?

Answer 11

Operands are either literals, variables, or sub-expressions.
Ex: using operators, 22 + 33, (4) * (5)

Question 12

What are sub-expressions?

Answer 12

Sub-expressions are expressions enclosed in parentheses, ( and )

Question 13

What are the Operator Priories for Calculations?

Answer 13

Highest to Lowest
* / %
+ -

Question 14

How does Operator Associativity work?

Answer 14

Just means the calculations read from left to right since that’s how Java reads.

Question 15

What are the two types of Mixed Mode Expressions?

Answer 15

Widening and Narrowing

Question 16

What is widening?

Answer 16

Taking a smaller value into a larger value
Ex: short to into (2 byte to 4 byte)
Note: can go from char to int

Question 17

What is narrowing?

Answer 17

Casting a bigger variable into a smaller variable
Ex: putting a ((int) 33.4) in front of a double

Question 18

What is a Unary Minus

Answer 18

• , can be placed immediately in front of an expression to negate the value of the expression.
  Ex: -(50-75) is 25

Question 19

What are the three operators for Booleans?

Answer 19

&&, ||, !

Question 20

What are the binary operators for Boolean?

Answer 20

&&, ||
Both appear between the two operands.

Question 21

What are the priorities of the Boolean operators?

Answer 21

! Is highest, followed by &&, followed by ||

Question 22

What are the Relational Operators?

Answer 22

Defined for comparing one value to another.

<, >, <=, >=, ==, !=

Question 23

What is the conditional operator?

Answer 23

?

<logical> ? <true> : <false>
Logical expression is some logical expression evaluating to true or false
</false></true></logical>

Question 24

The arithmetic, rational, and Boolean operator priorities?

Answer 24

++
—
- (unary minus)
!
new (object creation)
/
*
%
+
-
+ (String catenation)
<
<=
>
>=
==
!=
&&
||
?: (conditional operator)
= (assignment)
+= (assignment with operation)
-=
*=
/=
%=

Question 25

What does the String class work with?

Answer 25

Works with test strings and the Java String class is provided to facilitate the many things that programmers need to do with text strings.

Question 26

What is the difference between String type and primitive types?

Answer 26

The memory location associated with a primitive type contains the value (not an address) of the value. For example, an int variable will have a memory location reserved for it where the value of the variable is stored.
A variable (of type String) holds a reference to the value instead of holding the actual value.

Question 27

What does the new operator do?

Answer 27

The new operator is used to instantiate (to create) an object. new operator

Question 28

How to make a new line and tab in sysout?

Answer 28

“/n” for new line
“/t” for tab

Question 29

How to import JOptionPane?

Answer 29

Import javax.swing.JOptionPane;