Java quiz - Variables & Data types

Question 1:

What is the correct syntax to declare an integer variable named "num" in Java?

a) int num;

b) num int;

c) num = int;

d) declare num as int;

Answer: a) int num;

Question 2:

Which of the following is a valid identifier for a variable in Java?

a) 123variable

b) _variable

c) variable-1

d) variable#

Answer: b) _variable

Question 3:

Which of the following is NOT a primitive data type in Java?

a) int

b) float

c) string

d) boolean

Answer: c) string

Question 4:

What is the default value of an integer variable in Java if it is not initialized?

a) 0

b) 1

c) -1

d) null

Answer: a) 0

Question 5:

Which of the following data types is used to store characters in Java?

a) char

b) int

c) boolean

d) double

Answer: a) char

Question 6:

What is the maximum value that can be stored in an integer variable of type "short" in Java?

a) 127

b) 256

c) 32767

d) 65535

Answer: c) 32767

Question 7:

Which of the following is NOT a valid variable name in Java?

a) myVariable

b) 123Variable

c) _myVariable

d) $variable

Answer: b) 123Variable

Question 8:

Which of the following data types is used to store floating-point numbers with single precision in Java?

a) float

b) double

c) real

d) decimal

Answer: a) float

Question 9:

What is the correct way to declare a constant variable in Java?

a) final int num = 10;

b) constant int num = 10;

c) const int num = 10;

d) static int num = 10;

Answer: a) final int num = 10;

Question 10:

Which of the following data types is used to store true or false values in Java?

a) int

b) boolean

c) char

d) double

Answer: b) boolean