Java Data Types

Question 1

What is a variable?

Answer 1

A storage location in RAM

Question 2

What 2 things must a variable have?

Answer 2

A name and a data type

Question 3

What are 3 other words for variable “name”?

Answer 3

1) Identifier
2) Reference
3) Handle

Question 4

What are we doing when we declare a variable?

Answer 4

Binding the name to a specific memory address

Question 5

What can you NOT start a variable name with?

Answer 5

Number

Question 6

What three things can you start a variable name with?

Answer 6

1) Letter
2) Underscore
3) $

Question 7

What words can you not use for naming variables?

Answer 7

Java Reserved Words

Question 8

What kind of notation is used for naming variables?

Answer 8

camelBack

Question 9

What notation is used for naming classes?

Answer 9

TitleCase

Question 10

Why do we specify data type when declaring variables?

Answer 10

Tells OS how many bytes of memory to allocate and helps interpret data.

Question 11

How many characters are shared between ASCII and Unicode?

Answer 11

256

Question 12

Primitive data types are the only things in Java that are not _______. Why?

Answer 12

Objects, because they have no methods.

Question 13

How many primitive data types are there?

Answer 13

8

Question 14

How many numeric primitive data types are there?

Answer 14

6

Question 15

How many bits in a byte data type?

Answer 15

8 (1 byte)

Question 16

How many bits in a short?

Answer 16

16 (2 bytes)

Question 17

How many bits in an int?

Answer 17

32 (4 bytes)

Question 18

How many bits in a long?

Answer 18

64 (8 bytes)

Question 19

How many floating primitive types are there?

Answer 19

Two, float and double.

Question 20

How many bits in a float?

Answer 20

32 (4 bytes)

Question 21

How many bits in a double?

Answer 21

64 (8 bytes)

Question 22

What are the two non-numeric data types?

Answer 22

char and boolean

Question 23

How many bits in the char data type?

Answer 23

16 (2 bytes)

Question 24

What are the two default numeric primitive data types?

Answer 24

int and double

Question 25

How are floating numbers stored in Java?

Answer 25

A mantissa and an exponent

Question 26

What data type is a String?

Answer 26

Object

Question 27

What is the naming convention for constants?

Answer 27

UPPER_CASE_LETTERS

Question 28

What keyword is used when declaring a constant?

Answer 28

final

Question 29

What is a data literal?

Answer 29

The actual data value that appears in a program.

ex. ‘A’, or “Hello World”

Question 30

How do you get Java to interpret a very long number properly?

Answer 30

Add an ‘L’ to the end of it.

Question 31

When dividing integers by integers, Java ______ the answer.

Answer 31

Truncates

Question 32

Which operator returns the remainder from division?

Answer 32

Modulus (%)

Question 33

What are the unary operators?

Answer 33

(+ and -), denoting positive and negative

Question 34

What is the increment operator?

Answer 34

++

Question 35

When do you need to explicitly use type casting?

Answer 35

When assigning a larger data type to a variable with less capacity.
ex. assigning type int data to a variable of short.

Question 36

What is type casting?

Answer 36

Converts a value of one data type into a value of another data type.

Question 37

What is a common error of type casting?

Answer 37

Overflow