Method declaration in Java

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Introduction

Methods help you organize your code into small, reusable actions. They make your program easier to read and use.

When you want to repeat a task many times without rewriting code.

When you want to break a big problem into smaller, manageable parts.

When you want to give a name to a set of instructions for clarity.

When you want to reuse code in different places of your program.

When you want to make your program easier to test and fix.

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Syntax

Java

accessModifier returnType methodName(parameterList) {
    // method body
}

accessModifier controls who can use the method (like public or private).

returnType is the type of value the method gives back, or void if it returns nothing.

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Examples

line_end_arrow_notchA method that prints a greeting and returns nothing.

Java

public void sayHello() {
    System.out.println("Hello!");
}

line_end_arrow_notchA method that adds two numbers and returns the result.

Java

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

line_end_arrow_notchA method that checks if a number is even and returns true or false.

Java

public boolean isEven(int number) {
    return number % 2 == 0;
}

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Sample Program

This program has two methods: one to greet the user and one to add two numbers. The main method calls them to show how methods work.

Java

public class Main {
    public static void main(String[] args) {
        greetUser();
        int sum = addNumbers(5, 7);
        System.out.println("Sum: " + sum);
    }

    public static void greetUser() {
        System.out.println("Welcome to the program!");
    }

    public static int addNumbers(int x, int y) {
        return x + y;
    }
}

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Important Notes

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Method names usually start with a lowercase letter and use camelCase.

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Parameters inside parentheses are inputs the method needs to work.

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Use return to send a value back from the method.

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Summary

Methods group code into reusable blocks with a name.

They can take inputs (parameters) and give back outputs (return values).

Declaring methods helps keep your code clean and organized.