Oozie's docs have:
=oozie.email.from.address= - The from address to be used for mailing all emails (oozie@localhost by default).
However, the code does not seem to use a default when loading the prop from the Oozie conf. Thus if someone does not specify it, it causes an NPE when it tries to from a fromAddress object later.
Same applies to:
oozie.email.smtp.host - The host where the email action may find the SMTP server (localhost by default).