Java Programming Lesson 7 Part-2 | Functions / Methods in Java for Beginners

LESSON-7 PART-2

Functions / Methods in Java

✅ Here is Lesson-7: Functions / Methods in Java — Simple to Advanced 🚀

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📘 Lesson-7: Functions / Methods

A method is a block of code that performs a specific task and can be reused.

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✅ Why Methods?

✔ Avoid repeating code
✔ Make programs cleaner
✔ Easier to debug
✔ Improve organization

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✅ Syntax of a Method

returnType methodName(parameters) {
    // code
    return value; // (only if returnType is not void)
}

Example:

void greet() {
    System.out.println("Hello Java!");
}

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✅ Types of Methods

1️⃣ Method with No return, No parameters

public static void greet() {
    System.out.println("Welcome to Java!");
}

Call:

greet();

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2️⃣ Method with parameters

static void greetUser(String name) {
    System.out.println("Hello, " + name);
}

Call:

greetUser("Jitu");

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3️⃣ Method with return value

static int add(int a, int b) {
    return a + b;
}

Call:

int result = add(10, 20);
System.out.println(result);

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4️⃣ Method Overloading

Same method name but different parameters ✅

static int add(int a, int b) {
    return a + b;
}

static double add(double a, double b) {
    return a + b;
}

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✅ Full Example Program

public class Main {

    static void sayHello() {
        System.out.println("Hello Java");
    }

    static String fullName(String first, String last) {
        return first + " " + last;
    }

    static int multiply(int a, int b) {
        return a * b;
    }

    public static void main(String[] args) {
        sayHello();

        System.out.println(fullName("S.M.", "JITU HASAN"));
        int result = multiply(5, 4);
        System.out.println("Multiplication = " + result);
    }
}

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✅ Method Calling Rules

Feature	Keyword
Used inside main without creating object	static
Needs object to call	Non-static

Example (non-static):

class Test {
    void msg() {
        System.out.println("Hello");
    }

    public static void main(String[] args) {
        Test t = new Test();
        t.msg();
    }
}

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🧠 KEY TAKEAWAYS

✔ Methods = Reusable code
✔ Parameters send data → return values bring data back
✔ Static methods → direct call
✔ Non-static methods → require object
✔ Method Overloading allowed ✅

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📝 Practice Exercise

Write a program with:

• Method add() → returns sum

• Method sub() → returns subtraction

• Method display() → prints your full name

📌 Then call them from main() ✅

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✅ Lesson-7 PART-2 Completed!

➡ NEXT Lesson-7 Part-3: Scanner Input (more)