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Merge pull request #714 from psychomita/main
Added Java Methods page
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‎src/navs/documentation.js‎

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@@ -28,5 +28,5 @@ export const documentationNav = {
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pages['continue-statement'],
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],
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'Java Arrays': [pages['arrays'], pages['multidimensional-arrays']],
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'Java OOPS(I)': [pages['class-objects'], pages['static-keyword']],
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'Java OOPS(I)': [pages['class-objects'], pages['methods'], pages['static-keyword']],
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}

‎src/pages/docs/methods.mdx‎

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---
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title: Java Methods
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description: In this tutorial, we will learn how to implements methods or functions in Java.
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---
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## What is a method in Java?
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In Java, a method is a collection of statements designed to perform specific tasks and, optionally, return a result to the caller. A Java method can also execute a task without returning any value. Methods enable code reuse by eliminating the need to retype code. Importantly, in Java, every method must belong to a class.
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### Types of Methods in Java
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- `User-defined Methods`: Custom methods created by the programmer based on specific requirements.
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- `Standard Library Methods`: Built-in methods provided by Java, ready for immediate use.
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### Declaring a Java Method
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The basic syntax for a method declaration is:
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```java
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returnType methodName() {
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// method body
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}
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```
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1. **returnType:** Specifies the type of value returned by the method. If it doesn’t return a value, the return type is void.
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2. **methodName:** The identifier used to call the method.
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3. **method body:** Code inside `{ }` that defines the task to be performed.
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#### Example 1:
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```java
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int addNumbers() {
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// code
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}
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```
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In this example, `addNumbers()` is the method name, and its return type is `int`.
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#### For a more detailed declaration:
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```java
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modifier static returnType methodName(parameter1, parameter2, ...) {
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// method body
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}
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```
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1. **modifier:** Defines access type (e.g., public, private).
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2. **static:** If included, the method can be called without creating an object.
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3. **parameter1, parameter2, ...parameterN:** Values passed to the method.
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#### Example 2:
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The `sqrt()` method in the Math class is static, so it can be accessed as `Math.sqrt()` without creating an instance of Math.
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### Calling a Method in Java
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To use a method, call it by name followed by parentheses.
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#### Java Method Call Example
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```java
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class Main {
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public int addNumbers(int a, int b) {
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return a + b;
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}
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public static void main(String[] args) {
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int num1 = 25, num2 = 15;
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Main obj = new Main(); // Create object of Main class
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int result = obj.addNumbers(num1, num2);
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System.out.println("Sum is: " + result);
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}
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}
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```
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#### Output
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```bash
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Sum is: 40
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```
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Here, the `addNumbers()` method takes two parameters and returns their sum. Since it's not static, it requires an object to be called.
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### Method Return Types
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A method may or may not return a value. The return statement is used to return a value.
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#### Example 1: Method returns integer value
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```java
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public static int square(int num) {
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return num * num;
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}
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```
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#### Example 2: Method does not return any value
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```java
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// void keyword is used as function does not return any value
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public void printSquare(int num) {
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System.out.println(num * num);
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}
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```
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### Method Parameters
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Methods can accept parameters, which are values passed to the method.
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#### Examples
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- **With Parameters:** `int addNumbers(int a, int b)`
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- **Without Parameters:** `int addNumbers()`
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When calling a method with parameters, you must provide values for each parameter.
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#### Example of Method Parameters
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```java
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class Main {
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public void display1() {
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System.out.println("Method without parameter");
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}
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public void display2(int a) {
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System.out.println("Method with a single parameter: " + a);
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}
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public static void main(String[] args) {
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Main obj = new Main();
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obj.display1(); // No parameters
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obj.display2(24); // Single parameter
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}
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}
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```
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#### Output
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```bash
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Method without parameter
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Method with a single parameter: 24
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```
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**Note:** Java requires that argument types match the parameter types.
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### Standard Library Methods
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Java includes built-in methods available in the Java Class Library (JCL), which comes with the JVM and JRE.
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#### Example
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```java
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public class Main {
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public static void main(String[] args) {
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System.out.println("Square root of 4 is: " + Math.sqrt(4));
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}
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}
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```
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#### Output
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```bash
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Square root of 4 is: 2.0
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```
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### Advantages of Using Methods
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**Code Reusability:** Define once, use multiple times.
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```java
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private static int getSquare(int x) {
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return x * x;
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}
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public static void main(String[] args) {
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for (int i = 1; i <= 5; i++) {
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System.out.println("Square of " + i + " is: " + getSquare(i));
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}
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}
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```
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#### Output:
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```bash
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Square of 1 is: 1
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Square of 2 is: 4
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Square of 3 is: 9
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Square of 4 is: 16
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Square of 5 is: 25
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```
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**Improved Readability:** Grouping code into methods makes it easier to read and debug.

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