When you need to debug a JavaMail application, you can use the JavaMail debugging feature. The JavaMail component will generate debugging information that can be used for problem determination or tuning.
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:
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:
Note: Review the listed properties and values to verify that they correspond.