feat: add DataOutputStream example for serializing Student object

WHAT:
- Implemented `DataOutputStreamsExample` class.
- Created `Student11` class with fields: rollno, name, avg, dept.
- Used `DataOutputStream` with `FileOutputStream` to write student data into a file.

HOW:
1. Instantiated a `Student11` object and populated sample data.
2. Opened `FileOutputStream` pointing to `Student1.txt`.
3. Wrapped it with `DataOutputStream` for writing Java primitives in binary.
4. Wrote fields in a specific order:
   - `writeInt()` → roll number
   - `writeUTF()` → name
   - `writeUTF()` → department
   - `writeFloat()` → average
5. Closed streams safely after writing.
6. Data is saved in **binary format**, not human-readable text.

WHY:
- Demonstrates **manual serialization** using `DataOutputStream`.
- Ensures data is written in a **platform-independent binary format**.
- Reading must follow the **exact same order** using `DataInputStream`.

REAL-WORLD APPLICATIONS:
- Saving student records or user profiles in lightweight storage.
- Writing config/state data in binary (faster than plain text parsing).
- Efficient persistence in games, finance apps, or IoT systems.
- Forms the basis of custom serialization frameworks.

BENEFITS:
- Compact and efficient storage (binary instead of text).
- Machine-independent format due to `DataOutputStream`.
- Works with Java primitive types and UTF-encoded Strings.

NEXT IMPROVEMENTS:
- Add matching `DataInputStreamsExample` to read and reconstruct `Student11`.
- Refactor into reusable `writeStudent(Student11 student, File file)` method.
- Add try-with-resources for cleaner resource management.

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

Author: Someshdiwan

Section23JavaIOStreams/Serialisation Storing Data in a File/src/DataOutputStreamsExample.java

@@ -2,8 +2,7 @@
 import java.io.*;
 import java.io.FileOutputStream;
 
-class Student1
-{
+class Student11 {
     int rollno;
     String name;
     float avg;
@@ -12,7 +11,7 @@ class Student1
 
 public class DataOutputStreamsExample {
     public static void main(String[] args)throws Exception {
-        FileOutputStream fos=new FileOutputStream("C:\\Users\\somes\\Downloads\\JAVA SE\\Section23JavaIOStreams\\Serialisation Storing Data in a File\\MyJAVA\\Student2.txt");
+        FileOutputStream fos=new FileOutputStream("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/src/MyJAVA/Student1.txt");
         DataOutputStream dos=new DataOutputStream(fos);
 
         Student1 s1=new Student1();