GreenMail integration test sent email not being relayed to recipient - jakarta-mail

Question

I'm using greenmail for mail integration test, and came out with below code. The intention is to create 2 fake email servers that act as sender and recipient.
However when I ran the code, the test failed because the recipient doesn't receive the email. I've read some sample and faq from 'greenmail' site but can't find the explainations for this behavior. I hope someone could shed some light here.
Below is the test code:
#Before
public void setUp() {
// Setup fake smtp server.
ServerSetup smtpServer = new ServerSetup(Integer.parseInt(smtpPort), smtpHost, smtpProtocol);
serverA = new GreenMail(smtpServer);
serverA.start();
// Setup fake pop3 server.
ServerSetup pop3Server = new ServerSetup(Integer.parseInt(pop3Port), pop3Host, pop3Protocol);
serverB = new GreenMail(pop3Server);
serverB.start();
}
#Test
public void testSendEmailToAvailableMailboxReturnEmail() {
String senderMail = "sender.1#testmail.com";
String senderUsername = "sender1";
String senderPassword = "password123";
String receiverMail = "receiver.1#testmail.com";
String receiverUsername = "receiver1";
String receiverPassword = "pass567";
// Set mailbox for sender and receiver
serverA.setUser(senderMail, senderUsername, senderPassword);
serverB.setUser(receiverMail, receiverUsername, receiverPassword);
// Send email from serverA
String subject = "This is a test subject.";
String msg = "This is a plain test message.";
EmailModel emailModel = new EmailModel();
emailModel.setFrom(senderMail);
emailModel.setTo(receiverMail);
emailModel.setSubject(subject);
emailModel.setBody(msg);
emailModel.setSentDate(LocalDateTime.now());
emailModel.setBodyType(EmailModel.EMAIL_TYPE_TEXT);
// Using javamailsenderimpl to send the mail.
mailServiceImpl.send(emailModel);
// Retrieve email from ServerB
Session session = Session.getDefaultInstance(new Properties(), null);
try {
Store store = session.getStore(pop3Protocol);
store.connect(pop3Host, receiverUsername, receiverPassword);
Folder inbox = store.getFolder(BatchConstant.MAIL_INBOX);
inbox.open(Folder.READ_ONLY);
Message[] messages = inbox.getMessages();
Assert.assertNotNull(messages);
Assert.assertEquals(1, messages.length);
Assert.assertEquals(subject, messages[0].getSubject());
Assert.assertEquals(msg, String.valueOf(messages[0].getContent()).contains(msg));
} catch (MessagingException | IOException e) {
Assert.fail("Should be able to retrive sent mail.");
}
}
#After
public void tearDown() {
serverA.stop();
serverB.stop();
}
It fails at this line:
Assert.assertEquals(1, messages.length);
The log:
23:42:57.998 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'org.springframework.boot.test.mock.mockito.MockitoBeans'
23:42:58.014 [main] DEBUG com.icegreen.greenmail.util.GreenMail - Started services, performing check if all up
23:42:58.014 [smtp:127.111.44.233:25] DEBUG com.icegreen.greenmail.smtp.SmtpServer - Started smtp:127.111.44.233:25
23:42:58.029 [main] DEBUG com.icegreen.greenmail.util.GreenMail - Started services, performing check if all up
23:42:58.029 [pop3:127.124.244.10:110] DEBUG com.icegreen.greenmail.pop3.Pop3Server - Started pop3:127.124.244.10:110
23:42:58.061 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'getJavaMailSender'
DEBUG: JavaMail version 1.5.6
DEBUG: successfully loaded resource: /META-INF/javamail.default.providers
DEBUG: Tables of loaded providers
DEBUG: Providers Listed By Class Name: {com.sun.mail.smtp.SMTPSSLTransport=javax.mail.Provider[TRANSPORT,smtps,com.sun.mail.smtp.SMTPSSLTransport,Oracle], com.sun.mail.smtp.SMTPTransport=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle], com.sun.mail.imap.IMAPSSLStore=javax.mail.Provider[STORE,imaps,com.sun.mail.imap.IMAPSSLStore,Oracle], com.sun.mail.pop3.POP3SSLStore=javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLStore,Oracle], com.sun.mail.imap.IMAPStore=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Oracle], com.sun.mail.pop3.POP3Store=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Oracle]}
DEBUG: Providers Listed By Protocol: {imaps=javax.mail.Provider[STORE,imaps,com.sun.mail.imap.IMAPSSLStore,Oracle], imap=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Oracle], smtps=javax.mail.Provider[TRANSPORT,smtps,com.sun.mail.smtp.SMTPSSLTransport,Oracle], pop3=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Oracle], pop3s=javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLStore,Oracle], smtp=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle]}
DEBUG: successfully loaded resource: /META-INF/javamail.default.address.map
DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle]
DEBUG SMTP: useEhlo true, useAuth false
DEBUG SMTP: trying to connect to host "127.111.44.233", port 25, isSSL false
23:42:58.170 [smtp:127.111.44.233:25] DEBUG com.icegreen.greenmail.smtp.SmtpServer - Handling new client connection smtp:127.111.44.233:25<-/127.0.0.1:55846
220 /127.111.44.233 GreenMail SMTP Service v1.5.7 ready
DEBUG SMTP: connected to host "127.111.44.233", port: 25
EHLO MXXXXXXXXX
250 /127.111.44.233
DEBUG SMTP: use8bit false
MAIL FROM:<sender.1#testmail.com>
250 OK
RCPT TO:<receiver.1#testmail.com>
250 OK
DEBUG SMTP: Verified Addresses
DEBUG SMTP: receiver.1#testmail.com
DATA
354 Start mail input; end with <CRLF>.<CRLF>
Date: Tue, 12 Jun 2018 23:42:58 +0800 (SGT)
From: sender.1#testmail.com
To: receiver.1#testmail.com
Message-ID: <2074658615.2.1528818178201#MXXXXXXXXX>
Subject: This is a test subject.
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_Part_0_52514534.1528818178108"
------=_Part_0_52514534.1528818178108
Content-Type: multipart/related;
boundary="----=_Part_1_1046665075.1528818178123"
------=_Part_1_1046665075.1528818178123
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
This is a plain test message.
------=_Part_1_1046665075.1528818178123--
------=_Part_0_52514534.1528818178108--
.
23:42:58.217 [smtp:127.111.44.233:25<-/127.0.0.1:55846] INFO com.icegreen.greenmail.smtp.SmtpManager - Created user login receiver.1#testmail.com for address receiver.1#testmail.com with password receiver.1#testmail.com because it didn't exist before.
250 OK
DEBUG SMTP: message successfully delivered to mail server
QUIT
221 /127.111.44.233 Service closing transmission channel
23:42:58.264 [pop3:127.124.244.10:110] DEBUG com.icegreen.greenmail.pop3.Pop3Server - Handling new client connection pop3:127.124.244.10:110<-/127.0.0.1:55847
23:42:58.264 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: +OK POP3 GreenMail Server v1.5.7 ready
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - C: CAPA
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: +OK
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: UIDL
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: .
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - C: USER receiver1
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: +OK
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - C: PASS pass567
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: +OK
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - C: STAT
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: +OK 0 0
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - C: NOOP
23:42:58.279 [pop3:127.124.244.10:110<-/127.0.0.1:55847] DEBUG com.icegreen.greenmail.pop3.Pop3Connection - S: +OK noop rimes with poop
23:42:58.279 [main] DEBUG com.icegreen.greenmail.util.GreenMail - Stopping GreenMail ...
23:42:58.279 [main] DEBUG com.icegreen.greenmail.util.GreenMail - Stopping service smtp:127.111.44.233:25
23:42:58.295 [main] DEBUG com.icegreen.greenmail.smtp.SmtpServer - Stopping smtp:127.111.44.233:25
23:42:58.295 [main] DEBUG com.icegreen.greenmail.smtp.SmtpServer - Stopped smtp:127.111.44.233:25
23:42:58.295 [main] DEBUG com.icegreen.greenmail.util.GreenMail - Stopping GreenMail ...
23:42:58.295 [main] DEBUG com.icegreen.greenmail.util.GreenMail - Stopping service pop3:127.124.244.10:110
23:42:58.295 [main] DEBUG com.icegreen.greenmail.pop3.Pop3Server - Stopping pop3:127.124.244.10:110
23:42:58.295 [main] DEBUG com.icegreen.greenmail.pop3.Pop3Server - Stopped pop3:127.124.244.10:110
23:42:58.295 [main] DEBUG org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate - Retrieved ApplicationContext from cache with key [[MergedContextConfiguration#4e7dc304 testClass = MailServiceImplTest, locations = '{}', classes = '{class com.xxx.xoxoxo.mail.service.impl.MailServiceImpl, class com.xxx.xoxoxo.config.MailServiceConfig, class com.xxx.xoxoxo.batch.encryption.AesEncryptor, class com.xxx.xoxoxo.config.ApplicationProperties}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{enote.mail.host=127.111.44.233, enote.mail.port=25, enote.mail.protocol=smtp, enote.mail.encoding=UTF-8, enote.mail.auth=false, enote.mail.username=, enote.mail.password=}', contextCustomizers = set[org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer#59f99ea, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer#47c62251, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer#0, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer#0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer#589838eb], contextLoader = 'org.springframework.test.context.support.DelegatingSmartContextLoader', parent = [null]]]
23:42:58.295 [main] DEBUG org.springframework.test.context.cache - Spring test ApplicationContext cache statistics: [DefaultContextCache#645aa696 size = 1, maxSize = 32, parentContextCount = 0, hitCount = 2, missCount = 1]

Answer 1

GreenMail is a sandbox server. It will never route mail to another server.
What you want to do is create a single instance of GreenMail,
configured for both SMTP and POP3:
ServerSetup smtpServerSetup = ...
ServerSetup pop3ServerSetup = ...
GreenMail greenMail = new GreenMail(new ServerSetup[]{smtpServerSetup, pop3ServerSetup});
greenMail.start(); // Starts both smtp and pop3