Variables and formatting

Question 1

What is a variable in Java compared to in everyday life?

a) A storage container
b) A bookmark pointing to data in RAM
c) A function returning a value
d) A type of loop in the program

Answer 1

b) A bookmark pointing to data in RAM

Question 2

What is the scope of a variable used for in Java?

a) To determine the data type of the variable
b) To define which methods can access the variable
c) To set a value for the variable
d) To handle memory allocation

Answer 2

b) To define which methods can access the variable

Question 3

What is the primary purpose of a String variable in Java?

a) To store numerical values
b) To store ASCII and UTF-based text
c) To store boolean values
d) To store floating-point numbers

Answer 3

b) To store ASCII and UTF-based text

Question 4

What type of Java variable directly stores its literal value in memory?

a) Reference type
b) Primitive type
c) Static type
d) Dynamic type

Answer 4

b) Primitive type

Question 5

What is a Java reference type primarily used for?

a) To store literal values
b) To act as a bookmark pointing to another memory location
c) To handle boolean logic
d) To store primitive values

Answer 5

b) To act as a bookmark pointing to another memory location

Question 6

Which primitive type in Java stores a single ASCII/UTF character?

a) Byte
b) Int
c) Char
d) Float

Answer 6

c) Char

Question 7

What primitive type in Java is used for 64-bit floating point numbers?

a) Double
b) Float
c) Int
d) Long

Answer 7

a) Double

Question 8

Which Java primitive type is best for storing true/false values?

a) Boolean
b) Byte
c) Int
d) Char

Answer 8

a) Boolean

Question 9

What is the main benefit of using wrapper classes in Java?

a) They convert primitive data to object data
b) They decrease memory usage
c) They allow faster access to data
d) They provide additional functionality for primitive types

Answer 9

d) They provide additional functionality for primitive types

Question 10

In the HelloWorld example, why must the firstName variable be declared as static?

a) Because it is a primitive type
b) Because the class is static
c) Because it is a local variable
d) Because it is a reference type

Answer 10

b) Because the class is static

Question 11

What does the printf method in Java allow you to do?

a) Print a simple string
b) Add formatting rules to customize output
c) Declare variables
d) Format arrays automatically

Answer 11

b) Add formatting rules to customize output

Question 12

Which format specifier is used to insert a string variable in a printf statement?

a) %i
b) %s
c) %d
d) %c

Answer 12

b) %s

Question 13

Why did the ‘Hello world!’ and ‘Welcome to the world of Java, Aaron!’ outputs appear on the same line in the example?

a) Because they are printed from different methods
b) Because the program uses printf for both statements
c) Because there was no instruction to print them on separate lines
d) Because the System library does not handle strings

Answer 13

c) Because there was no instruction to print them on separate lines

Question 14

How do you instruct Java to print on a new line using printf?

a) Use \r
b) Use \n or %n
c) Use a new print statement
d) Use a variable

Answer 14

b) Use \n or %n

Question 15

What does the format specifier %d in printf represent?

a) Double precision numbers
b) Integer data
c) String data
d) Character data

Answer 15

b) Integer data

Question 16

What is the purpose of the System.lineSeparator() method in Java?

a) To automatically handle line endings across different operating systems
b) To add a new line to the output
c) To format text for specific operating systems
d) To replace the println method

Answer 16

a) To automatically handle line endings across different operating systems

Question 17

Why might Windows users need to use \r\n instead of just \n for new lines?

a) Because of differences in character encoding
b) Because \n does not work on Windows
c) Because Windows handles line endings differently than MacOS/Linux
d) Because \r\n is the default for all operating systems

Answer 17

c) Because Windows handles line endings differently than MacOS/Linux

Question 18

What does println do differently from printf in Java?

a) It adds a new line automatically
b) It does not accept variables
c) It formats output for the console
d) It requires more memory

Answer 18

a) It adds a new line automatically

Question 19

Which Java primitive type stores a 32-bit integer?

a) Float
b) Int
c) Long
d) Byte

Answer 19

b) Int

Question 20

What does the %s format specifier do in Java’s printf method?

a) Inserts a string variable into the output
b) Inserts an integer variable into the output
c) Adds a special character
d) Prints a floating-point number

Answer 20

a) Inserts a string variable into the output