add log

src/main/java/com/lhamacorp/mailserver/App.java

@@ -6,7 +6,7 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 @SpringBootApplication
 public class App {
 
-    public static void main(String[] args) {
+    static void main(String[] args) {
         SpringApplication.run(App.class, args);
     }
 

src/main/java/com/lhamacorp/mailserver/service/MailService.java

@@ -1,5 +1,7 @@
 package com.lhamacorp.mailserver.service;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.mail.SimpleMailMessage;
 import org.springframework.mail.javamail.JavaMailSender;
@@ -12,6 +14,8 @@ public class MailService {
 
     private final JavaMailSender mailSender;
 
+    private static final Logger log = LoggerFactory.getLogger(MailService.class);
+
     @Value("${spring.mail.username}")
     private String from;
 
@@ -28,6 +32,8 @@ public class MailService {
             message.setText(content);
 
             mailSender.send(message);
+
+            log.info("Mail sent to [{}]", to);
         } catch (Exception e) {
             throw new RuntimeException("Failed to send email: " + e.getMessage(), e);
         }