feat: demonstrate file reading using FileInputStream (Demo2)

WHAT:
- Implemented a simple program that reads file content byte by byte
  using `FileInputStream`.
- Casts each byte to a character and prints to console.
- Wrapped in try-catch to handle `IOException`.

HOW IT WORKS:
1. Open the file with `FileInputStream` pointing to a text file path.
2. Use `fin.read()` in a loop:
   - Returns an integer representing the next byte (0–255).
   - Returns -1 when EOF is reached, ending the loop.
3. Convert each byte to a `char` and print.
4. Exceptions (e.g., file not found) are handled gracefully.

KEY TAKEAWAYS:
- `FileInputStream` is a byte stream, suitable for both text and binary data.
- Always close streams to avoid resource leaks (try-with-resources is preferred).
- For text files, higher-level classes (`BufferedReader`, `FileReader`)
  are more efficient and encoding-aware.

REAL-WORLD USE CASES:
- Reading configuration files or logs at a low level.
- Inspecting binary files (images, PDFs) byte by byte.
- Implementing custom parsers or streaming systems where raw byte access is required.

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

Author: Someshdiwan

Section23JavaIOStreams/DemoCodes/TXT Files/Demo2.txt

@@ -1,4 +1,3 @@
-This Java program reads data from a file named myFile.txt,
-character by character, and prints each character on a new line.
+This Java program reads data from a file named myFile.txt, character by character, and prints each character on a new line.
 
-It uses FileInputStream and handles I/O exceptions if the file doesn't exist or can't be read.
+It uses FileInputStream and handles I/O exceptions if the file doesn't exist or can't be read.

Section23JavaIOStreams/DemoCodes/src/Demo2.java

@@ -1,24 +1,54 @@
-//Now Data Read in File
 import java.io.IOException;
 import java.io.FileOutputStream;
 import java.io.FileInputStream;
 
-class Demo2
-{
-    public static void main(String[] args)
-    {
-        try
-        {
+class Demo2 {
+    public static void main(String[] args) {
+        try {
             int data;
-            FileInputStream fin = new FileInputStream("C://Users//somes//Downloads//NoteApp//JavaEvolution-Learning-Growing-Mastering//Section23JavaIOStreams//DemoCodes\\TXT Files\\Demo2.txt");
-            while( (data = fin.read()) != -1)
-            {
+            FileInputStream fin = new FileInputStream("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/DemoCodes/TXT Files/Demo2.txt");
+            while ((data = fin.read()) != -1) {
                 System.out.println( (char) data);
             }
         }
-        catch (IOException e)
-        {
+        catch (IOException e) {
             System.out.println(e);
         }
     }
 }
+
+/*
+1. FileInputStream:
+   - Ye ek byte-oriented stream hai jo file ka content byte by byte read karta hai.
+   - Text files, images, audio, binary files sab ke liye use ho sakta hai.
+
+2. Code Explanation:
+   - `FileInputStream fin = new FileInputStream("path");`
+     → Ye file ko open karta hai read karne ke liye.
+   - `fin.read()` ek byte return karta hai (0–255 int).
+   - Jab end of file (EOF) aata hai, to -1 return hota hai.
+
+3. Loop:
+   - `while ((data = fin.read()) != -1)`
+   - Har iteration me ek byte read hota hai aur `(char)data` se usko character me convert karke print karte ho.
+   - Yahan `System.out.println((char)data);` likha hai → har ek character **nayi line me** print hoga.
+     Agar same line me chahiye to `System.out.print((char)data);` use karo.
+
+4. Exception Handling:
+   - Agar file nahi mili ya read karte waqt error aaya, to `IOException` catch block me handle hota hai.
+   - `System.out.println(e);` error message console par dikhata hai.
+
+5. Output:
+   - File ke andar jitna content hai wo line by line (char by char) console me print hoga.
+   - Example: File me `"Hello"` likha hai → Output:
+       H
+       e
+       l
+       l
+       o
+
+- `fin.close()` call karna zaroori hai after reading, warna file handle release nahi hoga (resource leak).
+- Tumhare code me `fin.close()` missing hai. Better hai try-with-resources use karna (Java 7+).
+- Agar tumhe performance chahiye, to `BufferedInputStream` ya `BufferedReader` prefer karo
+  (kyunki wo ek-ek byte ke bajay buffer me read karte hain).
+*/