Key Points and Sample Codes

• Key Points: Programming enables the solution of complex problems and automates repetitive tasks. Java is widely used due to its portability, object-oriented features, and extensive API.

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• Key Points: Variables store data values. Java supports several data types such as int, double, char, and boolean.

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• Key Points: Expressions are used to compute values. Assignment statements assign the result to a variable.

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• Key Points: Compound operators perform an operation and assignment in one step (e.g., +=, -=).

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• Key Points: Casting converts a variable from one type to another. Be aware of the ranges for data types to avoid overflow or unexpected behavior.

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20 Multiple-Choice Questions (MCQs)

1. What is one of the primary reasons Java is widely used? A) It is the fastest programming language. B) It can only be run on Windows. C) It is platform-independent due to the JVM. D) It does not support object-oriented programming.

2. Which data type would be best for storing a person's age? A) int B) double C) char D) boolean

3. What will the following Java statement print? System.out.println(6 + 9 * 2); A) 24 B) 15 C) 30 D) 21

4. What is the result of the following compound assignment? int a = 5; a *= 3; A) 8 B) 15 C) 5 D) 18

5. What will be the output of this Java code? double a = 100.234; int b = (int) a; System.out.println(b); A) 100.0 B) 100 C) 101 D) 100.234

6. What does the == operator check in Java? A) If two variables have the same type. B) If two variables store the same value. C) If two variables point to the same memory location. D) If two variables are constants.

7. What will happen if you try to store the number 256 in a byte variable in Java? A) It will compile and run without issue. B) It will cause a runtime error. C) It will not compile. D) The variable will wrap around to a negative value.

8. What does the following code snippet output? int x = 5; int y = x++; System.out.println(y); A) 5 B) 6 C) 10 D) 0

9. Which of the following is not a primitive data type in Java? A) int B) String C) boolean D) char

10. What will this code output? int a = 9; int b = a--; System.out.println(b); A) 9 B) 8 C) 10 D) 0

11. How do you declare a constant in Java? A) int const a = 10; B) final int a = 10; C) static int a = 10; D) constant int a = 10;

12. What will be the result of the following expression in Java? 15 + 3 * (4 / 2) A) 24 B) 18 C) 21 D) 15

13. What is the output of the following Java code? double x = 10.5; double y = x % 3; System.out.println(y); A) 1.5 B) 3.5 C) 2.5 D) 4.5

14. Which operator is used to compare two variables for inequality in Java? A) = B) == C) != D) <=

15. What is the default value of a boolean variable in Java? A) true B) false C) 0 D) null

16. Which keyword is used to create a new instance of an object in Java? A) struct B) new C) class D) this

17. What does the && operator signify in Java? A) OR B) AND C) NOT D) XOR

18. What is the range of values that can be assigned to a short variable in Java? A) -32768 to 32767 B) -128 to 127 C) 0 to 65535 D) -2147483648 to 2147483647

19. What will the following code print? int a = 10; int b = ++a; System.out.println(a + " " + b); A) 10 11 B) 11 11 C) 11 10 D) 10 10

20. What type of error will occur if you try to use an undeclared variable in Java? A) Syntax error B) Runtime error C) Logical error D) Compilation error