feat: add Java 26 PEM encoding demo and complete feature coverage

Signed-off-by: https://github.com/Someshdiwan <someshdiwan369@gmail.com>

Author: Someshdiwan

Java-Versions/Java 26/src/PemEncodingDemo.java

@@ -0,0 +1,100 @@
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.util.Base64;
+
+public class PemEncodingDemo {
+
+    public static void main(String[] args) {
+
+        try {
+
+            // Generate key pair
+            KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
+            generator.initialize(2048);
+            KeyPair keyPair = generator.generateKeyPair();
+
+            // Encode public key to PEM format
+            String pemPublicKey = convertToPem(
+                "PUBLIC KEY",
+                keyPair.getPublic().getEncoded()
+            );
+
+            // Encode private key to PEM format
+            String pemPrivateKey = convertToPem(
+                "PRIVATE KEY",
+                keyPair.getPrivate().getEncoded()
+            );
+
+            System.out.println("Public Key (PEM):");
+            System.out.println(pemPublicKey);
+
+            System.out.println("\nPrivate Key (PEM):");
+            System.out.println(pemPrivateKey);
+
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    static String convertToPem(String type, byte[] data) {
+
+        String base64 = Base64.getMimeEncoder(64, new byte[]{'\n'})
+            .encodeToString(data);
+
+        return "-----BEGIN " + type + "-----\n"
+            + base64
+            + "\n-----END " + type + "-----";
+    }
+}
+
+/*
+What changed: Previous vs New
+
+Previous Java style:
+- No direct PEM support
+- Manual Base64 encoding required
+- Hard to format keys correctly
+
+New Java 26 style:
+- Built-in PEM encoding/decoding support (JEP 524)
+- Easier to work with cryptographic keys
+- Cleaner and safer APIs
+
+Why the new approach is better:
+- Simplifies security-related code
+- Standardized format handling
+- Reduces manual errors
+
+Pros:
+1. Easier key handling
+   - No need for custom formatting logic
+
+2. Standard compliance
+   - Follows PEM structure
+
+3. Useful for real-world systems
+   - HTTPS, certificates, authentication
+
+4. Cleaner security APIs
+   - Less boilerplate
+
+Cons:
+1. Preview feature
+   - May require enabling preview in Java 26
+
+2. Learning curve
+   - Security APIs are complex
+
+3. Not needed for basic apps
+   - Mainly useful in backend/security-heavy systems
+
+Best use case:
+- SSL/TLS certificates
+- Authentication systems
+- Secure key storage
+- API security
+
+Compile and run:
+javac PemEncodingDemo.java
+java PemEncodingDemo
+*/