When a build finishes, hudson fails to send a mail with the result of the build.
This behaviour is new to version 1.180 (it worked with version 1.179).

We get the following trace (note there is a valid e-mail and an invalid one,
that's maybe the cause):

Sending e-mails to: valid@email.Com ipad7251orange-ftgroup.com
FATAL: gnu.mail.handler.TextPlain
java.lang.ClassCastException: gnu.mail.handler.TextPlain
at
javax.activation.MailcapCommandMap.getDataContentHandler(MailcapCommandMap.java:596)
at
javax.activation.MailcapCommandMap.createDataContentHandler(MailcapCommandMap.java:550)
at javax.activation.DataHandler.getDataContentHandler(DataHandler.java:611)
at javax.activation.DataHandler.writeTo(DataHandler.java:315)
at javax.mail.internet.MimeUtility.getEncoding(MimeUtility.java:248)
at javax.mail.internet.MimeBodyPart.updateHeaders(MimeBodyPart.java:1268)
at javax.mail.internet.MimeMessage.updateHeaders(MimeMessage.java:2012)
at javax.mail.internet.MimeMessage.saveChanges(MimeMessage.java:1980)
at javax.mail.Transport.send(Transport.java:97)
at hudson.tasks.MailSender.execute(MailSender.java:74)
at hudson.tasks.Mailer._perform(Mailer.java:75)
at hudson.tasks.Mailer.perform(Mailer.java:69)
at
hudson.tasks.BuildStepCompatibilityLayer.perform(BuildStepCompatibilityLayer.java:33)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:273)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:261)
at hudson.model.Build$RunnerImpl.post2(Build.java:136)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:246)
at hudson.model.Run.run(Run.java:677)
at hudson.model.Build.run(Build.java:101)
at hudson.model.ResourceController.execute(ResourceController.java:70)
at hudson.model.Executor.run(Executor.java:65)

Thanks.