feat: add File class usage example to explore file and directory properties

WHAT:
- Implemented `FileClassExample` to demonstrate working with the `File` class in Java.
- Checked if a given path is a directory using `isDirectory()`.
- Retrieved and printed all files and subdirectories inside the specified directory using `listFiles()`.
- Displayed both the file name (`getName()`) and its full path (`getPath()`).

WHY:
- The `File` class is the entry point for interacting with the file system in Java.
- It provides metadata about files/directories (existence, permissions, visibility) and allows directory traversal.
- Understanding `File` is essential before using advanced APIs like `NIO` or `Files`.

HOW:
1. Created a `File` object pointing to a directory.
2. Used `isDirectory()` to check if the path is a directory.
3. Called `listFiles()` to get all files and directories inside the path.
4. Iterated over the list and printed details (name and absolute path).

ADDITIONAL CAPABILITIES (commented in code):
- `setReadOnly()` → make a file read-only.
- `setWritable(true)` → allow writing.
- `isFile()` → check if path points to a file.
- `isHidden()` → check if the file is hidden.
- `setLastModified()` → change last modified timestamp.

REAL-WORLD USE CASES:
- Building file explorers or directory tree visualizers.
- Implementing batch file processing (e.g., scanning `.txt` or `.log` files).
- Checking file permissions before performing read/write operations.
- Implementing utilities for cleanup, monitoring, or backup of directories.
- Pre-validation in applications (e.g., ensuring config files exist before startup).

NOTES:
- The `File` class only represents paths and metadata; it does not read/write file contents.
- For actual content operations, streams (`FileInputStream`, `FileOutputStream`) or `java.nio.file.Files` are needed.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section23JavaIOStreams/src/FileClassExample.java

@@ -4,11 +4,9 @@
 public class FileClassExample {
     public static void main(String[] args)throws Exception {
         //Accessing properties of file.
-
-        File f=new File("C://Users\\somes\\Downloads\\JAVA SE\\Section23JavaIOStreams\\src\\MyJAVA");
+        File f = new File("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/src/MyJAVA");
 
        /*
-
        f.setReadOnly();
        f.setWritable(true);
        FileOutputStream fos = new FileOutputStream("C://Users\\\\somes\\\\Downloads\\\\JAVA SE\\\\Section23JavaIOStreams\\\\src\\\\MyJAVA");
@@ -17,10 +15,8 @@ public static void main(String[] args)throws Exception {
        f.isFile();
        f.isDirectory();
        f.isHidden();
-
        */
 
-
         System.out.println(f.isDirectory());
 
         /*
@@ -33,10 +29,40 @@ public static void main(String[] args)throws Exception {
         */
 
         File list[]=f.listFiles();
-        for(File x:list)
-        {
+
+        for(File x:list) {
             System.out.println(x.getName()+" ");
             System.out.println(x.getPath());
         }
     }
-}
+}
+
+/*
+1. File Class:
+   - java.io.File ek abstract representation hai file ya directory path ka.
+   - Actual data read/write nahi karta, sirf properties aur metadata handle karta hai.
+
+2. Common Methods:
+   - f.isFile() → check karta hai ki given path ek file hai ya nahi.
+   - f.isDirectory() → check karta hai ki given path ek directory hai.
+   - f.isHidden() → check karta hai ki file hidden hai ya nahi.
+   - f.setReadOnly(), f.setWritable(true/false) → permissions change karte hain.
+   - f.setLastModified(time) → last modified timestamp set karta hai.
+   - f.list() → directory ke andar ke file/directory names string array me return karta hai.
+   - f.listFiles() → directory ke andar ke files ko File objects ke array me return karta hai.
+
+3. Code Flow:
+   - File object banaya pointing to directory `"MyJAVA"`.
+   - `f.isDirectory()` se check kiya directory hai ya nahi.
+   - `listFiles()` se directory ke andar ki files iterate karke unke `getName()` aur `getPath()` print kiya.
+
+4. Use Cases:
+   - File explorer ya directory traversal banane ke liye.
+   - Files ki properties (read-only, hidden, permissions) check/update karne ke liye.
+   - File search, log management, aur serialization me kaafi common.
+
+
+✔ File class → metadata aur properties ke liye.
+✔ Read/Write actual data ke liye alag streams (FileInputStream, FileOutputStream).
+✔ Directory traversal → `list()` ya `listFiles()`.
+*/