bael-8311: implementation (#17115)

* bael-8311: implementation

* feedback

---------

Co-authored-by: technoddy <[email protected]>

Author: imsurajmishra

core-java-modules/core-java-networking-2/src/main/java/com/baeldung/mail/EmailService.java

@@ -42,29 +42,41 @@ public EmailService(String host, int port) {
 
     public static void main(String... args) {
         try {
-            new EmailService("smtp.mailtrap.io", 25, "87ba3d9555fae8", "91cb4379af43ed")
-              .sendMail();
+            new EmailService("smtp.mailtrap.io", 25, "87ba3d9555fae8", "91cb4379af43ed").sendMail();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 
     public void sendMail() throws Exception {
 
-        Session session = Session.getInstance(prop, new Authenticator() {
-            @Override
-            protected PasswordAuthentication getPasswordAuthentication() {
-                return new PasswordAuthentication(username, password);
-            }
-        });
+        Session session = getSession();
 
         Message message = new MimeMessage(session);
         message.setFrom(new InternetAddress("[email protected]"));
         message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected]"));
         message.setSubject("Mail Subject");
+        String msg = "This is my first email using JavaMailer";
+        message.setContent(getMultipart(msg));
 
+        Transport.send(message);
+    }
+
+    public void sendMailToMultipleRecipients() throws Exception {
+        Session session = getSession();
+
+        Message message = new MimeMessage(session);
+        message.setFrom(new InternetAddress("[email protected]"));
+        message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected], [email protected]"));
+        message.addRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected], [email protected]"));
+        message.setSubject("Mail Subject");
         String msg = "This is my first email using JavaMailer";
+        message.setContent(getMultipart(msg));
+
+        Transport.send(message);
+    }
 
+    private Multipart getMultipart(String msg) throws Exception {
         MimeBodyPart mimeBodyPart = new MimeBodyPart();
         mimeBodyPart.setContent(msg, "text/html; charset=utf-8");
 
@@ -80,17 +92,24 @@ protected PasswordAuthentication getPasswordAuthentication() {
         multipart.addBodyPart(mimeBodyPart);
         multipart.addBodyPart(mimeBodyPartWithStyledText);
         multipart.addBodyPart(attachmentBodyPart);
+        return multipart;
+    }
 
-        message.setContent(multipart);
-
-        Transport.send(message);
+    private Session getSession() {
+        Session session = Session.getInstance(prop, new Authenticator() {
+            @Override
+            protected PasswordAuthentication getPasswordAuthentication() {
+                return new PasswordAuthentication(username, password);
+            }
+        });
+        return session;
     }
 
     private File getFile() throws Exception {
         URI uri = this.getClass()
-          .getClassLoader()
-          .getResource("attachment.txt")
-          .toURI();
+            .getClassLoader()
+            .getResource("attachment.txt")
+            .toURI();
         return new File(uri);
     }
 

core-java-modules/core-java-networking-2/src/test/java/com/baeldung/mail/EmailServiceLiveTest.java

@@ -1,5 +1,6 @@
 package com.baeldung.mail;
 
+import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 
 import java.io.IOException;
@@ -11,7 +12,9 @@
 import com.icegreen.greenmail.junit.GreenMailRule;
 import com.icegreen.greenmail.util.ServerSetupTest;
 
+import jakarta.mail.Address;
 import jakarta.mail.MessagingException;
+import jakarta.mail.internet.InternetAddress;
 import jakarta.mail.internet.MimeMessage;
 import jakarta.mail.internet.MimeMultipart;
 
@@ -24,7 +27,8 @@ public class EmailServiceLiveTest {
 
     @Before
     public void setup() {
-        emailService = new EmailService("localhost", greenMail.getSmtp().getPort());
+        emailService = new EmailService("localhost", greenMail.getSmtp()
+            .getPort());
     }
 
     @Test
@@ -42,29 +46,43 @@ public void givenEmailMessageWithAttachment_whenEmailIsSent_MessageIsReceived()
         assertEquals("sample attachment content", attachmentContentsFrom(receivedMessage));
     }
 
+    @Test
+    public void givenEmailMessageWithMultipleRecipients_whenEmailIsSent_AllRecipientReceivedMessage() throws Exception {
+        emailService.sendMailToMultipleRecipients();
+
+        MimeMessage[] receivedMessages = greenMail.getReceivedMessages();
+        assertEquals(4, receivedMessages.length);
+
+        for (MimeMessage mimeMessage : receivedMessages) {
+            Address[] recipients = new Address[4];
+            recipients[0] = new InternetAddress("[email protected]");
+            recipients[1] = new InternetAddress("[email protected]");
+            recipients[2] = new InternetAddress("[email protected]");
+            recipients[3] = new InternetAddress("[email protected]");
+            assertArrayEquals(recipients, mimeMessage.getAllRecipients());
+        }
+    }
+
     private static String subjectFromMessage(MimeMessage receivedMessage) throws MessagingException {
         return receivedMessage.getSubject();
     }
 
     private static String emailTextFrom(MimeMessage receivedMessage) throws IOException, MessagingException {
-        return ((MimeMultipart) receivedMessage.getContent())
-          .getBodyPart(0)
-          .getContent()
-          .toString();
+        return ((MimeMultipart) receivedMessage.getContent()).getBodyPart(0)
+            .getContent()
+            .toString();
     }
 
     private static String emailStyledTextFrom(MimeMessage receivedMessage) throws IOException, MessagingException {
-        return ((MimeMultipart) receivedMessage.getContent())
-            .getBodyPart(1)
+        return ((MimeMultipart) receivedMessage.getContent()).getBodyPart(1)
             .getContent()
             .toString();
     }
 
     private static String attachmentContentsFrom(MimeMessage receivedMessage) throws Exception {
-        return ((MimeMultipart) receivedMessage.getContent())
-          .getBodyPart(2)
-          .getContent()
-          .toString();
+        return ((MimeMultipart) receivedMessage.getContent()).getBodyPart(2)
+            .getContent()
+            .toString();
     }
 
 }