feat: add DataInputStream-based deserialization with Student1 example

WHAT:
- Created `Student1` class with fields: rollno, name, dept, avg.
- Implemented `DataInputStreamsExample2` to read student data from file
  `Student2.txt` using `DataInputStream`.

HOW:
1. Opened file via `FileInputStream` and wrapped in `DataInputStream`.
2. Instantiated `Student1` object.
3. Read data in the same sequence as written:
   - readInt()   → rollno
   - readUTF()   → name
   - readUTF()   → dept
   - readFloat() → avg
4. Printed student details to the console.
5. Properly closed the input stream.

KEY POINTS:
- **Order matters:** Data must be read in the same order and type in
  which it was written, otherwise runtime errors occur.
- `DataInputStream` simplifies reading Java primitives and strings
  without manual parsing.
- Complements `DataOutputStream` for serialization.

REAL-WORLD APPLICATIONS:
- Custom serialization format for performance-sensitive apps.
- Storing and retrieving structured student or employee records.
- Lightweight persistence layer for local file-based storage.
- Useful in games, logging, or legacy system integrations.

IMPROVEMENTS:
- Use try-with-resources for auto-closing streams.
- Add validation/error handling if file data is corrupted.
- Add corresponding `DataOutputStream` writer to complete the cycle.

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

Author: Someshdiwan

Section23JavaIOStreams/Serialisation Storing Data in a File/src/DataInputStreamsExample2.java

@@ -0,0 +1,33 @@
+import java.io.*;
+
+class Student1 {
+    int rollno;
+    String name;
+    String dept;
+    float avg;
+}
+
+public class DataInputStreamsExample2 {
+    public static void main(String[] args) throws Exception {
+        FileInputStream fis = new FileInputStream("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/src/MyJAVA/Student2.txt");
+        DataInputStream dis = new DataInputStream(fis);
+
+        // Serialisation: using DataInput and DataOutput Streams.
+
+        Student1 s = new Student1();
+
+        s.rollno = dis.readInt();
+        s.name = dis.readUTF();
+        s.dept = dis.readUTF();
+        s.avg = dis.readFloat();
+
+        // Order Must be same. to read the data in the file using Input Stream.
+
+        System.out.println("Roll No: " + s.rollno);
+        System.out.println("Name: " + s.name);
+        System.out.println("Average: " + s.avg);
+        System.out.println("Dept: " + s.dept);
+
+        dis.close();
+    }
+}