When you need to debug a JavaMail application, you can use the JavaMail debugging feature. Enabling the debugger triggers the JavaMail component of WebSphere Application Server to print the following data to the stdout output stream:

• interactions with the mail servers

• properties of the mail session

This output stream is redirected to the SystemOut.log file for the specific application server.

The mail debugger functions on a per session basis. To enable the JavaMail debugging feature:

1. Open the administrative console.

2. Click...

   Resources | Mail Providers | mail_session | Mail Session | mail session

3. Click Debug. Debug is enabled for just that session.

4. Click Apply or OK.

Example

DEBUG: not loading system providers in <java.home>/lib DEBUG  
not loading optional custom providers file: 
/META-INF/javamail.providers DEBUG: successfully loaded default providers  
DEBUG  Tables of loaded providers 
DEBUG: Providers listed by Class Name:
{com.sun.mail.smtp.SMTPTransport=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc], 
com.sun.mail.imap.IMAPStore=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Sun Microsystems, Inc], 
com.sun.mail.pop3.POP3Store=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Sun Microsystems, Inc]}
DEBUG:  Providers Listed By Protocol:
{imap=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Sun Microsystems,
Inc], pop3=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Sun Microsystems, Inc], 
smtp=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc]}
DEBUG: not loading optional address map file: 
/META-INF/javamail.address.map *** In SessionFactory.getObjectInstance,
  The default SessionAuthenticator is based on:
   store_user = john_smith    store_pw = abcdef 
*** In SessionFactory.getObjectInstance, parameters in the new session:
    mail.store.protocol="imap"
    mail.transport.protocol="smtp"
    mail.imap.user="john_smith"
    mail.smtp.host="smtp.coldmail.com"
    mail.debug="true" 
    ws.store.password="abcdef"
    mail.from="john_smith@coldmail.com"
    mail.smtp.class="com.sun.mail.smtp.SMTPTransport"
    mail.imap.class="com.sun.mail.imap.IMAPStore"
    mail.imap.host="coldmail.com"
DEBUG: mail.smtp.class property exists and points to com.sun.mail.smtp.SMTPTransport DEBUG SMTP: 
useEhlo true, useAuth false DEBUG: SMTPTransport trying to connect to host "smtp.coldmail.com", port 25    

javax.mail.SendFailedException: Sending failed; 
      nested exception is:
      javax.mail.MessagingException: Unknown SMTP host: smtp.coldmail.com;
       nested exception is java.net.UnknownHostException: smtp.coldmail.com        
       at javax.mail.Transport.send0(Transport.java:219) 
       at javax.mail.Transport.send(Transport.java:81)
       at ws.mailfvt.SendSaveTestCore.runAll(SendSaveTestCore.java:48)
       at testers.AnyTester.main(AnyTester.java:130)

This output illustrates a connection failure to a Simple Mail Transfer Protocol (SMTP) server because a fictitious name, smtp.coldmail.com, is specified as the server name. The following list provides tips on reading the previous sample of debugger output:

• The lines headed by DEBUG are printed by the JavaMail run-time, while the two lines headed by *** are printed by the WebSphere environment run-time.

• The first two lines say that some configuration files are skipped. At run-time the JavaMail component attempts to load a number of configuration files from different locations. All those files are not required. If a required file cannot be accessed, however, the JavaMail component creates an exception. In this sample, there is no exception and the third line announces that default providers are loaded.

• The next few lines, headed by either Providers listed by Class Name or Providers Listed by Protocols, show the protocol providers that are loaded. The three providers that are listed are the default protocol providers that come under the WebSphere built-in mail provider. They are the protocols SMTP, IMAP, and POP3, respectively. If you install special protocol providers (or, in JavaMail terminology, service providers) and these providers are used in the current mail session, you see them listed here with the default providers.

• The two lines headed by *** and the few lines below them are printed by WebSphere Application Server to show the configuration properties of the current mail session. Although these properties are listed by their internal name rather than the name you establish in the administrative console, you can easily recognize the relationships between them. For example, the property mail.store.protocol corresponds to the Protocol Name property in the Store Access section of the mail session configuration page.

  Note: Review the listed properties and values to verify that they correspond.

• The few lines above the exception stack show the JavaMail activities when sending a message. First, the JavaMail API recognizes that the transport protocol is set to SMTP and that the provider com.sun.mail.smtp.SMTPTransport exists. Next, the parameters used by SMTP, useEhlo and useAuth, are shown. Finally, the log shows the SMTP provider trying to connect to the mail server smtp.coldmail.com.

• Next is the exception stack. This data indicates that the specified mail server either does not exist or is not functioning.