I have Hudson 1.146 and email-ext 1.2 installed. I previously had email
notifications working for my job using the email config provided by Hudson.

I configured the email-ext plugin to send emails on successful builds, but an
NPE is thrown in the hudson.Util.encode() method when it attempts to send the email.

I tried this with the option for "E-mail Notification" checked and with it
unchecked, and the NPE occurred for both scenarios.

Here is the output from my job ( the email address was xxx'ed out )

---------------------

BUILD SUCCESSFUL
Total time: 2 minutes 25 seconds
Recording fingerprints
Recording test results
Sending e-mails to: xxx@xxx.com
FATAL: null
java.lang.NullPointerException
at hudson.Util.encode(Util.java:400)
at
hudson.plugins.emailext.ExtendedEmailPublisher.transformText(ExtendedEmailPublisher.java:244)
at
hudson.plugins.emailext.ExtendedEmailPublisher.createMail(ExtendedEmailPublisher.java:195)
at
hudson.plugins.emailext.ExtendedEmailPublisher.sendMail(ExtendedEmailPublisher.java:167)
at
hudson.plugins.emailext.ExtendedEmailPublisher._perform(ExtendedEmailPublisher.java:155)
at
hudson.plugins.emailext.ExtendedEmailPublisher.perform(ExtendedEmailPublisher.java:124)
at hudson.model.Build$RunnerImpl.post2(Build.java:138)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:244)
at hudson.model.Run.run(Run.java:597)
at hudson.model.Build.run(Build.java:103)
at hudson.model.ResourceController.execute(ResourceController.java:66)
at hudson.model.Executor.run(Executor.java:62)