Java Variables MCQ

Java is one of the most popular programming languages in the world. If you're a beginner, it's crucial to understand the fundamentals of Java, and variables are a great place to start. Test your knowledge with this Java Variables Quiz consisting of 10 multiple-choice questions.

Each question is followed by the correct answer and an explanation to help reinforce your knowledge.

1. Which of the following is a valid variable declaration in Java?

a) int 1variable;
b) float myFloat = 5.6;
c) char 'a';
d) string name = "John";

Answer:

b) float myFloat = 5.6;

Explanation:

In Java, variable names cannot begin with numbers (option a), cannot have single quotes (option c), and type names are case-sensitive, meaning string is incorrect, it should be String (option d).

2. Which data type is used to store a single character in Java?

a) char
b) String
c) int
d) single

Answer:

a) char

Explanation:

In Java, the char data type is used to store a single character.

3. How many bytes does an int data type occupy in Java?

a) 1
b) 2
c) 4
d) 8

Answer:

c) 4

Explanation:

In Java, an int data type occupies 4 bytes.

4. Which of the following is the correct way to declare multiple variables of the same type?

a) int a; int b; int c;
b) int a, b, c;
c) int a, b = 5, c;
d) All of the above

Answer:

d) All of the above

Explanation:

All the given options are valid ways to declare multiple variables in Java.

5. Which keyword in Java is used for constant variables?

a) const
b) static
c) constant
d) final

Answer:

d) final

Explanation:

In Java, the final keyword is used to declare constant variables.

6. What will be the default value of an int variable if not initialized in a class?

a) null
b) 0
c) NaN
d) -1

Answer:

b) 0

Explanation:

If an int variable is a member of a class and is not initialized, its default value is 0.

7. Which of the following is a valid variable name in Java?

a) -myVar
b) 3times
c) my_var
d) float

Answer:

c) my_var

Explanation:

Variable names in Java can contain letters, digits, underscores, and dollar signs. They cannot start with a digit or contain Java-reserved words like float.

8. The boolean data type in Java can have values:

a) 1 and 0
b) true and false
c) Yes and no
d) Any integer value

Answer:

b) true and false

Explanation:

The boolean data type in Java can only have the values true or false.

9. Which data type can be used to store large decimal numbers in Java?

a) int
b) float
c) double
d) char

Answer:

c) double

Explanation:

The double data type is used to store large decimal numbers in Java.

This quiz should give beginners a basic understanding of Java variables. If you got all the answers correct, well done! If not, don't worry; practice makes perfect. Keep studying and practicing!


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