On my Mac, if I execute the following code in Java 6:

System.out.println(InetAddress.getLocalHost().getHostName());

I got:

5855pns93223

But when run in Java 7, I got:

5855pns93223.nznmba.com

This causes problem with some existing Java mail code, with exception like:

Caused by: javax.mail.MessagingException: 501 5.0.0 HELO requires domain address
        at com.sun.mail.smtp.SMTPTransport.issueCommand(SMTPTransport.java:1363)
        at com.sun.mail.smtp.SMTPTransport.helo(SMTPTransport.java:838)
        at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:375)
        at javax.mail.Service.connect(Service.java:275)
        at javax.mail.Service.connect(Service.java:156)
        at javax.mail.Service.connect(Service.java:105)
        at javax.mail.Transport.send0(Transport.java:168)
        at javax.mail.Transport.send(Transport.java:98)

This isn't good for unit testing when I need to run them locally.

Solution ?

Add two entries to my /etc/hosts:

127.0.0.1       5855pns93223
127.0.0.1       5855pns93223.nznmba.com

A hack, I know, but a quick fix at least for now :)