"Le temps perdu" (the lost time) including extra hours trying to solve this problem ...

I managed to have a sort of "hello world" of email sending working with exchange and javamail.

First, let's make things clear. I'm in a corporate environment. I am forced to use exchange, I have to deal with the proxy, a slow machine and a lack of documentation.
Fortunately, the web access is not too restrained. 

Thank you http://stackoverflow.com !
With all the threads openned on javamail + exchange I could 'compile' something.

If ever that can help someone else than me, here are the ingredients I used (might differ in your environment)
  • use TLS props.put("mail.smtp.starttls.enable","true");
  • use port 587  (not 25, not 685)
  • use a javax.mail.Authenticator
  • add the necessary certificates to the keystore used by your VM

    On a *nix system, try   find / -name cacerts |more
    and find / -name .keystore |more
  • You will find the certificates from your browser settings
Other findings
  • McAffee protection against 'mass emailing worms'  prevents you from developing on your dev station
What I should not write
  • Write simple test programs on the PROD env. to be sure it CAN work
And now a poem
LE TEMPS PERDU (de Jacques Prévert)
Devant la porte de l'usine
le travailleur soudain s'arrête
le beau temps l'a tiré par la veste
et comme il se retourne
et regarde le soleil
tout rouge tout rond
souriant dans son ciel de plomb
il cligne de l'oeil
Dis-donc camarade soleil
tu ne trouves pas
que c'est plutôt con
de donner une journée pareille
à un patron?