Chapter 4 - Operators

Question 1

Relational operators

Answer 1

always result in a boolean value (true or false)

Question 2

There are 6 relational operators

Answer 2

>
>=
<
<= 
==  (Equality Operator)
!=   (Equality Operator)

Question 3

Equality Operators

Answer 3

There are two: == and !=
4 things can be tested:
numbers, characters, booleans and reference variables

Question 4

When comparing characters

Answer 4

Java uses Unicode value of character as the numeric value

Question 5

instanceof operator

Answer 5

is for reference variables only, and checks if an object is of a particular type

Question 6

instanceof operator

Answer 6

can be used only to test Objects (or null) against class types that are of the same hierarchy

Question 7

for interfaces

Answer 7

an object passes the instanceof test if any of its superclasses implement the interface on the right side of the instanceof operator

Question 8

There are 4 primary math operators

Answer 8

add, subtract, multiply and divide

Question 9

The remainder operator (%)

Answer 9

returns the remainder of a division

Question 10

Expressions are evaluated from left to right

Answer 10

unless you add parenthesis, or unless some operators have higher precedence

Question 11

*,/, and %

Answer 11

operators have higher precedence than + and -

Question 12

If either operand is a string

Answer 12

the + operator concatenates the operands

Question 13

If both operands are numeric (in string concatenations)

Answer 13

the + operator adds the operands

Question 14

Prefix operators ++ and – run

Answer 14

before the value is used in the expression

Question 15

Postfix operators ++ and – run

Answer 15

after the value is used in the expression

Question 16

In any expression

Answer 16

both operands are fully evaluated before the operator is applied

Question 17

Variables marked final

Answer 17

cannot be incremented or decremented

Question 18

Ternary/Conditional operators returns

Answer 18

one of two values based on whether boolean expression is true or false
returns the value after the ? if expression is true
returns the value after the : if expression is false

Question 19

The exam covers 6 ternary operators

Answer 19

&, |, ^, !, &&, and ||

Question 20

Logical operators work with two expressions

Answer 20

except for (!) that must resolve to boolean values

Question 21

The && and & operators

Answer 21

return true only if BOTH operands are true

Question 22

The || and | operators

Answer 22

returns true if EITHER or BOTH operands are true

Question 23

The && and ||

Answer 23

are known as SHORT CIRCUIT operators

Question 24

The && operand does not evaluate the right operand

Answer 24

if the left operand is false

Question 25

The || operand does not evaluate the right operand

Answer 25

if the left operand is true

Question 26

The & and | operators

Answer 26

always evaluate both operands

Question 27

The ^ operator (called the logical XOR)

Answer 27

returns true if exactly one operand is true

Question 28

The ! operator (called the inversion operator)

Answer 28

returns the opposite value of the boolean operand it precedes