JavaMail hangs up does not send mail nor throws exception when sending with attachment.

Question

So basically i have a problem that has been reported, but none of the answers solved in my case.
I'm trying to send a mail with attachment using java mail, and it hangs in the transport.Send without sending an exception.
I've put the debug to true to try to understand what's going on and the result that i get is this:
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.SMTPSSLTransport=javax.mail.Provider[TRANSPORT,smtps,com.sun.mail.smtp.S  MTPSSLTransport,Sun Microsystems, Inc],  com.sun.mail.smtp.SMTPTransport=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.
SMTPTransport,Sun Microsystems, Inc],  com.sun.mail.imap.IMAPSSLStore=javax.mail.Provider[STORE,imaps,com.sun.mail.imap.IMAPSSLSto  re,Sun Microsystems, Inc], com.sun.mail.pop3.POP3SSLStore=javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLSto re,Sun M
icrosystems, 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:   {imaps=javax.mail.Provider[STORE,imaps,com.sun.mail.imap.IMAPSSLStore,Sun Microsystems,   Inc], imap=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Sun Microsystems,   Inc], smtps=javax.mail.Provider[TRANSPORT,
smtps,com.sun.mail.smtp.SMTPSSLTransport,Sun Microsystems, Inc],  pop3=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Sun Microsystems, Inc],  pop3s=javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLStore,Sun Microsystems,   Inc], smtp=java
x.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc]}
DEBUG: not loading optional address map file: /META-INF/javamail.address.map
i've tried set the both connection timeout proprieties to 5000 but it stil does nott generate an exception. i've tried to chage the try catch block to catch Exception rather than MessagingException but it still does not generate an exception.
So i have another environment where using the same mail server and code it is working and i.ve generated the debug message and the next message is
DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc]
I don't understand why it blocks here and why this message is not shown. i don't think its a connection problem. maybe a configuration issue, so i'm triyng to understand whats going wrong.
Any help would be appreciated. Thanks.

Answer 1

Based on the debug output, you're using a very old version of JavaMail.  You should consider upgrading.
The debug output shows no attempt to connect to any server, so it appears that something is going wrong even before then.
If the program is really blocked, try to get a stack trace showing where it's blocked.
Also, try catching Throwable to make sure you're not missing some kind of unexpected failure.
Do you have a standalone application, or is it running in some sort of application server?
What version of the JDK are you using?