Programming and Java Fundamentals

Module Review and Exercises

ReadingPreview

You are viewing a free preview lesson.

Module Overview

এই module-এ আমরা programming এবং Java-এর fundamental concepts শিখেছি।

আমরা শুরু করেছি computer কীভাবে program execute করে তা দিয়ে। এরপর Java development environment setup, syntax, variables, data types, Strings, operators, input, conditions এবং loops ব্যবহার করে একটি complete console-based grade calculator তৈরি করেছি।

এই review lesson-এর উদ্দেশ্য:

Module 1-এর গুরুত্বপূর্ণ conceptগুলো পুনরায় দেখা
Concepts-এর মধ্যে connection বোঝা
Common mistake identify করা
Mixed programming problems solve করা
পরবর্তী Object-Oriented Programming module-এর জন্য প্রস্তুত হওয়া

Module Learning Outcomes

এই module শেষ করার পর আপনি পারবেন:

Programming এবং program execution explain করতে
Java source code compile এবং run করতে
JDK, JRE, JVM এবং bytecode-এর ভূমিকা বুঝতে
Java syntax follow করে program লিখতে
Variables, constants এবং data types ব্যবহার করতে
Strings process এবং compare করতে
Operators দিয়ে expressions তৈরি করতে
Type conversion এবং casting করতে
Scanner দিয়ে user input নিতে
if-else এবং switch দিয়ে decision নিতে
for, while এবং do-while loops ব্যবহার করতে
break এবং continue দিয়ে loop control করতে
একটি interactive console program তৈরি করতে

Part 1: Programming Fundamentals Review

What Is Programming?

Programming হলো computer-কে একটি নির্দিষ্ট কাজ করানোর জন্য instructions তৈরি করার process।

একটি program সাধারণত:

Input নেয়
Data process করে
Decision নেয়
Output তৈরি করে

Example:

Input:
Two numbers

Process:
Add the numbers

Output:
Total

Java example:

int firstNumber = 10;
int secondNumber = 20;

int total =
        firstNumber + secondNumber;

System.out.println(total);

Output:

Algorithm

Algorithm হলো একটি problem solve করার ordered step-by-step procedure।

Example: দুটি number-এর মধ্যে largest value বের করা।

1. Read first number
2. Read second number
3. Compare the numbers
4. Display the larger number
5. If equal, display that they are equal

Java implementation:

int firstNumber = 20;
int secondNumber = 30;

if (firstNumber > secondNumber) {
    System.out.println(
            firstNumber + " is larger"
    );
} else if (secondNumber > firstNumber) {
    System.out.println(
            secondNumber + " is larger"
    );
} else {
    System.out.println(
            "The numbers are equal"
    );
}

Part 2: How Java Programs Execute

Java source file:

Main.java

Compilation:

javac Main.java

Compiler bytecode তৈরি করে:

Main.class

Execution:

java Main

Flow:

Java source code
        ↓
Java compiler
        ↓
Bytecode
        ↓
JVM
        ↓
Machine instructions
        ↓
Program output

JDK, JRE, and JVM

JDK

JDK হলো Java application develop করার complete toolkit।

এতে থাকে:

Java compiler
Runtime components
Development tools
Debugging tools

JRE

JRE Java program run করার runtime environment।

JVM

JVM Java bytecode execute করে।

Simplified relationship:

JDK
 └── Runtime components
      └── JVM

Modern Java distribution-এ standalone JRE সবসময় আলাদাভাবে দেওয়া নাও হতে পারে, তবে conceptual difference জানা গুরুত্বপূর্ণ।

Bytecode

Java compiler source code-কে platform-independent bytecode-এ convert করে।

এই কারণে একই compiled Java bytecode different operating system-এর compatible JVM-এ run করতে পারে।

Write once
Run on a compatible JVM

Part 3: Java Program Structure

Basic Java program:

public class Main {

    public static void main(String[] args) {
        System.out.println(
                "Hello, Java!"
        );
    }
}

Important parts:

public class Main class declaration
main() program entry point
{} code block
; statement terminator
System.out.println() console output

Case Sensitivity

Java case-sensitive।

String learnerName = "Sakib";

এগুলো আলাদা identifiers:

learnerName
LearnerName
LEARNERNAME

Wrong:

system.out.println("Hello");

Correct:

System.out.println("Hello");

Comments

Single-line:

// Calculate the total

Multi-line:

/*
 * Calculate the final result.
 */

Documentation comment:

/**
 * Displays the student result.
 */

Comments code explain করে, কিন্তু obvious code repeat করা উচিত নয়।

Part 4: Variables and Constants

Variable

Variable একটি named storage location।

String studentName = "Jalisa";
int age = 30;
double score = 85.5;
boolean active = true;

General syntax:

type variableName = value;

Reassignment

int score = 80;

score = 90;

Final value:

Constant

যে value reassign করা উচিত নয়, সেটি final দিয়ে declare করা যায়।

final int PASSING_MARK = 40;

Class-level constant:

static final int MAXIMUM_MARK = 100;

Constant naming convention:

UPPER_SNAKE_CASE

Meaningful Names

Poor:

int x = 40;

Better:

int passingMark = 40;

Constant হলে:

static final int PASSING_MARK = 40;

Part 5: Primitive Data Types

Java-এর আটটি primitive type:

Type	Common Use
`byte`	Very small integer
`short`	Small integer
`int`	General integer
`long`	Large integer
`float`	Lower-precision decimal
`double`	General decimal
`char`	Single UTF-16 code unit
`boolean`	`true` or `false`

Integer Types

byte smallValue = 100;
short shortValue = 30_000;
int learnerCount = 1_000_000;
long globalCount = 8_000_000_000L;

long literal-এর জন্য অনেক ক্ষেত্রে L suffix প্রয়োজন।

Floating-Point Types

float temperature = 36.5F;
double average = 85.75;

float literal-এর জন্য F suffix প্রয়োজন।

General decimal calculation-এর জন্য double commonly used।

Character

char grade = 'A';

char single quotes ব্যবহার করে।

Boolean

boolean enrollmentOpen = true;
boolean accountBlocked = false;

Overflow

int value = Integer.MAX_VALUE;

value++;

System.out.println(value);

Output:

-2147483648

Integer overflow silent wrap-around করতে পারে।

Integer Division

int result = 5 / 2;

Result:

Decimal result:

double result = 5.0 / 2;

Result:

2.5

Part 6: Strings and Text Values

String primitive type নয়। এটি একটি class এবং reference type।

String learnerName = "Subu";
String courseName =
        "Java and OOP Foundation";

String double quotes ব্যবহার করে।

String text = "Java";

char single quotes ব্যবহার করে।

char letter = 'J';

Empty, Blank, and Null

String empty = "";
String blank = "   ";
String missing = null;

Checks:

empty.isEmpty();
blank.isBlank();

Null-safe validation:

if (
        learnerName != null
        && !learnerName.isBlank()
) {
    System.out.println(
            "Valid learner name"
    );
}

String Concatenation

String firstName = "Subu";
String lastName = "Sakib";

String fullName =
        firstName + " " + lastName;

Concatenation and Arithmetic

System.out.println(
        "Total: " + 10 + 20
);

Output:

Total: 1020

Correct numeric calculation:

System.out.println(
        "Total: " + (10 + 20)
);

Output:

Total: 30

Common String Methods

String value =
        "  Java Foundation  ";

value.length();
value.strip();
value.toUpperCase();
value.toLowerCase();
value.contains("Java");
value.startsWith("Java");
value.endsWith("Foundation");
value.indexOf("Foundation");
value.replace("Java", "OOP");

String Equality

Wrong:

if (role == "ADMIN") {
}

Correct:

if ("ADMIN".equals(role)) {
}

Case-insensitive:

if (
        "ADMIN".equalsIgnoreCase(role)
) {
}

String Immutability

String language = "java";

language.toUpperCase();

System.out.println(language);

Output:

java

Correct:

language =
        language.toUpperCase();

Part 7: Operators and Expressions

Arithmetic Operators

+
-
*
/
%

Example:

int subtotal =
        price * quantity;

Assignment Operators

=
+=
-=
*=
/=
%=

Example:

int total = 10;

total += 5;

Final:

Comparison Operators

==
!=
>
<
>=
<=

Example:

boolean passed =
        mark >= 40;

Logical Operators

&&
||
!

Example:

boolean canEnroll =
        age >= 18
        && emailVerified
        && !accountBlocked;

Increment and Decrement

count++;
count--;

Prefix:

int result = ++count;

Postfix:

int result = count++;

Standalone usage preferred:

count++;

Operator Precedence

int result = 10 + 5 * 2;

Result:

With parentheses:

int result = (10 + 5) * 2;

Result:

Part 8: Type Conversion and Casting

Widening Conversion

int learnerCount = 100;

long totalLearners =
        learnerCount;

Automatic।

Narrowing Conversion

double average = 85.75;

int wholeAverage =
        (int) average;

Result:

Casting rounds করে না। Decimal part truncate করে।

Casting Before Division

Correct:

double average =
        (double) total / count;

Too late:

double average =
        (double) (total / count);

Second version-এ integer division আগে হয়ে যায়।

String to Number

int age =
        Integer.parseInt("30");

double price =
        Double.parseDouble("4990.50");

long population =
        Long.parseLong("8000000000");

Number to String

String ageText =
        String.valueOf(30);

Safe Long-to-Int Conversion

long value = 1000L;

int result =
        Math.toIntExact(value);

Out-of-range value হলে exception হবে।

Part 9: Reading User Input

Import:

import java.util.Scanner;

Create Scanner:

Scanner scanner =
        new Scanner(System.in);

Read full line:

String learnerName =
        scanner.nextLine();

Read integer:

int age =
        scanner.nextInt();

Recommended consistent approach:

int age =
        Integer.parseInt(
                scanner
                        .nextLine()
                        .strip()
        );

`nextInt()` and `nextLine()` Issue

int age =
        scanner.nextInt();

scanner.nextLine();

String name =
        scanner.nextLine();

Extra nextLine() remaining newline consume করে।

Input Validation

if (scanner.hasNextInt()) {
    int age =
            scanner.nextInt();
} else {
    String invalidInput =
            scanner.nextLine();

    System.out.println(
            "Invalid input: "
            + invalidInput
    );
}

Part 10: Conditional Statements

Basic If

if (mark >= 40) {
    System.out.println("Passed");
}

If-Else

if (mark >= 40) {
    System.out.println("Passed");
} else {
    System.out.println("Failed");
}

Else-If

if (mark >= 80) {
    System.out.println("A");
} else if (mark >= 70) {
    System.out.println("B");
} else if (mark >= 60) {
    System.out.println("C");
} else {
    System.out.println("Needs improvement");
}

Specific or higher threshold আগে রাখতে হয়।

Range Validation

boolean validMark =
        mark >= 0
        && mark <= 100;

Invalid:

boolean invalidMark =
        mark < 0
        || mark > 100;

Independent Conditions

if (mark >= 40) {
    System.out.println("Passed");
}

if (mark >= 80) {
    System.out.println("Distinction");
}

দুটি block-ই execute হতে পারে।

Part 11: Switch Review

Arrow-Style Switch

String dashboard = switch (role) {
    case "ADMIN" ->
            "Admin dashboard";

    case "INSTRUCTOR" ->
            "Instructor dashboard";

    case "LEARNER" ->
            "Learner dashboard";

    default ->
            "Unknown dashboard";
};

Multiple Labels

String dayType = switch (dayNumber) {
    case 1, 2, 3, 4, 5 ->
            "Weekday";

    case 6, 7 ->
            "Weekend";

    default ->
            "Invalid";
};

Switch vs If-Else

Use switch for:

Exact menu option
Role
Status
Enum
Fixed command

Use if-else for:

Numeric range
Multiple boolean conditions
Null checks
Inequality
Complex business rules

Part 12: Loop Review

For Loop

for (int number = 1; number <= 5; number++) {
    System.out.println(number);
}

Suitable when repetition count বা range জানা।

While Loop

int number = 1;

while (number <= 5) {
    System.out.println(number);

    number++;
}

Suitable when loop condition-based এবং repetition count unknown।

Do-While Loop

int option;

do {
    option =
            Integer.parseInt(
                    scanner
                            .nextLine()
                            .strip()
            );
} while (option != 3);

Body অন্তত একবার execute হয়।

Accumulator

int total = 0;

for (int number = 1; number <= 5; number++) {
    total += number;
}

String Traversal

String learnerName = "Sumu";

for (
        int index = 0;
        index < learnerName.length();
        index++
) {
    System.out.println(
            learnerName.charAt(index)
    );
}

Condition:

index < learnerName.length()

<= ব্যবহার করলে invalid index error হবে।

Break

for (int number = 1; number <= 10; number++) {
    if (number == 5) {
        break;
    }

    System.out.println(number);
}

Continue

for (int number = 1; number <= 5; number++) {
    if (number == 3) {
        continue;
    }

    System.out.println(number);
}

Output:

Part 13: Complete Mixed Example

নিচের programটি learner names নিয়ে একটি simple result summary তৈরি করে।

import java.util.Scanner;

public class Main {

    static final int PASSING_MARK = 40;

    public static void main(String[] args) {
        Scanner scanner =
                new Scanner(System.in);

        System.out.print(
                "Enter learner name: "
        );

        String learnerName =
                scanner
                        .nextLine()
                        .strip();

        while (learnerName.isBlank()) {
            System.out.println(
                    "Learner name is required."
            );

            System.out.print(
                    "Enter learner name: "
            );

            learnerName =
                    scanner
                            .nextLine()
                            .strip();
        }

        System.out.print(
                "Enter subject count: "
        );

        int subjectCount =
                Integer.parseInt(
                        scanner
                                .nextLine()
                                .strip()
                );

        while (
                subjectCount < 1
                || subjectCount > 10
        ) {
            System.out.println(
                    "Subject count must be between 1 and 10."
            );

            System.out.print(
                    "Enter subject count: "
            );

            subjectCount =
                    Integer.parseInt(
                            scanner
                                    .nextLine()
                                    .strip()
                    );
        }

        int totalMarks = 0;
        int failedSubjects = 0;

        for (
                int subject = 1;
                subject <= subjectCount;
                subject++
        ) {
            int mark;

            do {
                System.out.print(
                        "Enter mark for subject "
                        + subject
                        + ": "
                );

                mark =
                        Integer.parseInt(
                                scanner
                                        .nextLine()
                                        .strip()
                        );

                if (mark < 0 || mark > 100) {
                    System.out.println(
                            "Invalid mark."
                    );
                }
            } while (mark < 0 || mark > 100);

            totalMarks += mark;

            if (mark < PASSING_MARK) {
                failedSubjects++;
            }
        }

        double average =
                totalMarks
                / (double) subjectCount;

        boolean passed =
                failedSubjects == 0;

        String grade;

        if (!passed) {
            grade = "F";
        } else if (average >= 80) {
            grade = "A";
        } else if (average >= 70) {
            grade = "B";
        } else if (average >= 60) {
            grade = "C";
        } else if (average >= 50) {
            grade = "D";
        } else {
            grade = "E";
        }

        String message = switch (grade) {
            case "A" ->
                    "Excellent work, "
                    + learnerName
                    + "!";

            case "B" ->
                    "Very good work, "
                    + learnerName
                    + ".";

            case "C" ->
                    "Good progress, "
                    + learnerName
                    + ".";

            case "D", "E" ->
                    "You passed, but keep practising.";

            case "F" ->
                    "Review the failed subjects and try again.";

            default ->
                    "Result unavailable.";
        };

        System.out.println();
        System.out.println(
                "=== Result Summary ==="
        );

        System.out.println(
                "Learner: " + learnerName
        );

        System.out.println(
                "Total: " + totalMarks
        );

        System.out.println(
                "Average: "
                + "%.2f".formatted(
                        average
                )
        );

        System.out.println(
                "Failed subjects: "
                + failedSubjects
        );

        System.out.println(
                "Grade: " + grade
        );

        System.out.println(
                "Result: "
                + (
                        passed
                                ? "Passed"
                                : "Failed"
                )
        );

        System.out.println(
                "Message: " + message
        );

        scanner.close();
    }
}

Part 14: Debugging Exercises

Exercise 1: Integer Division

Problem:

int total = 250;
int count = 3;

double average =
        total / count;

Expected decimal average।

Fix the code.

Exercise 2: String Equality

Problem:

String learnerName = "Sakib";

if (learnerName == "Sakib") {
    System.out.println("Matched");
}

Rewrite using the recommended comparison method।

Exercise 3: Null Check

Problem:

String courseName = null;

if (
        !courseName.isBlank()
        && courseName != null
) {
    System.out.println("Valid");
}

Fix the condition order।

Exercise 4: Infinite Loop

Problem:

int number = 1;

while (number <= 5) {
    System.out.println(number);
}

Fix the loop।

Exercise 5: Wrong Update Direction

for (
        int number = 1;
        number <= 10;
        number--
) {
    System.out.println(number);
}

Fix the loop।

Exercise 6: Invalid String Index

String name = "Nur";

for (
        int index = 0;
        index <= name.length();
        index++
) {
    System.out.println(
            name.charAt(index)
    );
}

Fix the condition।

Exercise 7: Fall-Through

int option = 1;

switch (option) {
    case 1:
        System.out.println("Create");

    case 2:
        System.out.println("Update");

    default:
        System.out.println("Unknown");
}

Fix using:

Traditional break
Arrow-style switch

Exercise 8: Invalid Range Logic

boolean validMark =
        mark >= 0
        || mark <= 100;

Fix the expression।

Exercise 9: Product Accumulator

int product = 0;

for (int number = 1; number <= 5; number++) {
    product *= number;
}

Fix the initial value।

Exercise 10: Sentinel Processing

Problem:

while (true) {
    int number =
            Integer.parseInt(
                    scanner.nextLine()
            );

    total += number;

    if (number == -1) {
        break;
    }
}

Ensure -1 is not added to the total।

Part 15: Short Programming Exercises

Exercise 1: Personal Greeting

Create variables:

Name: Jalisa
Country: Estonia
Learning: Java

Output:

Jalisa is learning Java in Estonia.

Exercise 2: Twin Ages

Create variables for:

Subu age
Sumu age

Print whether their ages are equal।

Exercise 3: Nur's Score

Given:

int score = 78;

Print:

Passed or failed
Grade
Whether distinction eligible

Distinction threshold:

Exercise 4: Largest Number

Read three integers and print the largest one।

Exercise 5: Number Classification

Read an integer and print:

Positive, negative, or zero
Even or odd

Exercise 6: Multiplication Table

Read a number and print its table from 1 to 10।

Exercise 7: Sum of a Range

Read start and end values।

Calculate the sum of all numbers in the range।

Example:

Start: 1
End: 5
Total: 15

Exercise 8: Factorial

Read a non-negative integer and calculate its factorial।

Exercise 9: Count Vowels

Read an English word or sentence and count vowels।

Exercise 10: Reverse Text

Read a String and reverse it using a loop।

Exercise 11: Password Attempts

Correct password:

java123

Maximum attempts:

Output:

Access granted

অথবা:

Account locked

Exercise 12: Menu Calculator

Create menu:

1. Add
2. Subtract
3. Multiply
4. Divide
5. Exit

Use:

do-while
switch
Division-by-zero validation

Exercise 13: Running Total

Read numbers until user enters 0।

Calculate:

Total
Count
Average
Highest
Lowest

Exercise 14: Grade Calculator

Read:

Learner name
Subject count
Marks

Calculate:

Total
Average
Pass/fail
Grade

Use names such as:

Sakib
Jalisa
Subu
Sumu
Nur

during testing।

Part 16: Predict the Output

Question 1

int value = 5;

System.out.println(
        value++ + 2
);

System.out.println(value);

Question 2

System.out.println(
        "Total: " + 10 + 20
);

Question 3

int total = 0;

for (int number = 1; number <= 3; number++) {
    total += number;
}

System.out.println(total);

Question 4

int number = 3;

while (number >= 1) {
    System.out.println(number);

    number--;
}

Question 5

for (int number = 1; number <= 5; number++) {
    if (number == 3) {
        continue;
    }

    System.out.println(number);
}

Question 6

String name = "Subu";

System.out.println(
        name.charAt(
                name.length() - 1
        )
);

Question 7

double result =
        (double) (5 / 2);

System.out.println(result);

Question 8

String role = "instructor";

String dashboard = switch (
        role.toUpperCase()
) {
    case "INSTRUCTOR" ->
            "Harbor";

    case "LEARNER" ->
            "Dashboard";

    default ->
            "Unknown";
};

System.out.println(dashboard);

Predict the Output Answers

Answer 1

7
6

Postfix increment প্রথম expression-এ old value 5 ব্যবহার করে, তারপর value 6 হয়।

Answer 2

Total: 1020

Answer 3

Answer 4

3
2
1

Answer 5

Answer 6

Answer 7

2.0

Integer division আগে হয়েছে।

Answer 8

Harbor

Part 17: Module Assessment

Section A: Multiple Choice

Question 1

Java source file compile করার command কোনটি?

A. java Main.java
B. javac Main.java
C. compile Main.java
D. jdk Main.java

Question 2

Java program-এর entry point কোন method?

A. start()
B. run()
C. main()
D. execute()

Question 3

কোনটি primitive type নয়?

A. int
B. boolean
C. String
D. char

Question 4

String content compare করার recommended method কোনটি?

A. ==
B. equals()
C. compare
D. same()

Question 5

5 / 2 result কী?

A. 2.5
B. 2
C. 3
D. Compilation error

Question 6

Valid mark range check কোনটি?

A. mark >= 0 || mark <= 100
B. 0 <= mark <= 100
C. mark >= 0 && mark <= 100
D. mark > 0 && mark < 100

Question 7

যে loop body অন্তত একবার execute হয়:

A. for
B. while
C. do-while
D. None

Question 8

Current iteration skip করে:

A. break
B. return
C. continue
D. yield

Question 9

Switch expression block থেকে value দেয়:

A. break
B. yield
C. continue
D. next

Question 10

String-এর last valid index:

A. length()
B. length() + 1
C. length() - 1
D. 0

Section B: True or False

Java case-sensitive।
String একটি primitive type।
== String content comparison-এর recommended method।
while body zero times execute হতে পারে।
do-while-এর শেষে semicolon প্রয়োজন।
Casting always rounds decimal values।
break পুরো program terminate করে।
continue current iteration skip করে।
Scanner.nextLine() full line পড়তে পারে।
index <= text.length() safe String traversal condition।

Section C: Short Answers

JDK, JRE এবং JVM-এর difference লিখুন।
Variable এবং constant-এর difference লিখুন।
Empty String, blank String এবং null-এর difference লিখুন।
Widening এবং narrowing conversion explain করুন।
nextInt()-এর পরে nextLine() skip হওয়ার কারণ explain করুন।
Multiple if এবং else-if-এর difference লিখুন।
for, while এবং do-while কখন ব্যবহার করবেন?
break, continue এবং return-এর difference লিখুন।
Integer division avoid করার একটি example লিখুন।
Loop-এর off-by-one error কী?

Assessment Answers

Multiple Choice

True or False

True
False
False
True
True
False
False
True
True
False

Final Practical Challenge

একটি console-based Learner Progress Tracker তৈরি করুন।

Program-এর menu:

1. Add learner result
2. View grading rules
3. Exit

Learner result-এর জন্য নিন:

Learner name
Completed lesson count
Total lesson count
Assignment score
Final assessment score

Rules:

Lesson counts negative হতে পারবে না
Completed lessons total lessons-এর বেশি হতে পারবে না
Scores 0–100 range-এর মধ্যে হতে হবে
Course completion percentage calculate করতে হবে
Final score:

Assignment score × 40%
Final assessment score × 60%

Course passed হবে যদি:

Completion percentage 100%
Final score at least 40

Grade:

80–100 → A
70–79  → B
60–69  → C
50–59  → D
40–49  → E
Below 40 → F

Output example:

=== Learner Progress Report ===
Learner: Nur
Completed lessons: 21 of 21
Completion: 100.00%
Assignment score: 75.00
Final assessment: 85.00
Final score: 81.00
Grade: A
Result: Passed

Programটিতে ব্যবহার করুন:

Constants
Scanner
Input validation
do-while
switch
if-else
Type conversion
Formatted output
break এবং continue

Module Summary

Module 1-এ আমরা শিখেছি:

Programming problem-solving process
Java source compilation এবং execution
JDK, runtime components, JVM এবং bytecode
Java program structure এবং syntax
Variables এবং constants
Primitive data types
Strings এবং text processing
Arithmetic, comparison এবং logical operators
Type conversion এবং casting
Console input with Scanner
Conditional execution
Traditional এবং modern switch
for, while এবং do-while loops
break এবং continue
Validation, accumulation এবং reporting
Complete console application development

এই foundation-এর ওপর পরবর্তী module-এ আমরা Java-এর Object-Oriented Programming concepts শুরু করব।

Next Module

পরবর্তী module-এ আমরা শিখব:

Object-Oriented Programming Foundations

Topics:

Object-Oriented Programming কী
Class এবং object
Fields এবং methods
Object creation
Constructors
this keyword
Encapsulation
Access modifiers
Static এবং instance members
Method parameters এবং return values
Object relationships
Practical class-based project

Module Overview

Module Learning Outcomes

Part 1: Programming Fundamentals Review

What Is Programming?

Algorithm

Part 2: How Java Programs Execute

JDK, JRE, and JVM

JDK

JRE

JVM

Bytecode

Part 3: Java Program Structure

Case Sensitivity

Comments

Part 4: Variables and Constants

Variable

Reassignment

Constant

Meaningful Names

Part 5: Primitive Data Types

Integer Types

Floating-Point Types

Character

Boolean

Overflow

Integer Division

Part 6: Strings and Text Values

Empty, Blank, and Null

String Concatenation

Concatenation and Arithmetic

Common String Methods

String Equality

String Immutability

Part 7: Operators and Expressions

Arithmetic Operators

Assignment Operators

Comparison Operators

Logical Operators

Increment and Decrement

Operator Precedence

Part 8: Type Conversion and Casting

Widening Conversion

Narrowing Conversion

Casting Before Division

String to Number

Number to String

Safe Long-to-Int Conversion

Part 9: Reading User Input

nextInt() and nextLine() Issue

Input Validation

Part 10: Conditional Statements

Basic If

If-Else

Else-If

Range Validation

Independent Conditions

Part 11: Switch Review

Arrow-Style Switch

Multiple Labels

Switch vs If-Else

Part 12: Loop Review

For Loop

While Loop

Do-While Loop

Accumulator

String Traversal

Break

Continue

Part 13: Complete Mixed Example

Part 14: Debugging Exercises

Exercise 1: Integer Division

Exercise 2: String Equality

Exercise 3: Null Check

Exercise 4: Infinite Loop

Exercise 5: Wrong Update Direction

Exercise 6: Invalid String Index

Exercise 7: Fall-Through

Exercise 8: Invalid Range Logic

Exercise 9: Product Accumulator

Exercise 10: Sentinel Processing

`nextInt()` and `nextLine()` Issue