Single Sign-on (Deprecated)
Oxygen XML Author Eclipse plugin implements the Single sign-on property (meaning that you can
      log on once and gain access to multiple services without being prompted to log on for each of
      them), based on the Kerberos protocol and relies on a ticket-granting ticket
        (TGT) that Oxygen XML Author Eclipse plugin obtains from the operating system.
    Restriction: 
This Single sign-on support is not available for SharePoint
        integrations.
To turn on the Kerberos-based authentication, you need to add the
      following system property in the eclipse.ini
        configuration file (on a separate line after the 
  -vmargs
      parameter):-Djavax.security.auth.useSubjectCredsOnly=false