/**
     * Get the value for the key 'mail.hostname'. <br>
     * The value is, e.g.  <br>
     * comment: Hostname for the mail server.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getMailHostname();

    /**
     * Get the value for the key 'mail.hostname' as {@link Integer}. <br>
     * The value is, e.g.  <br>

  qualified domain name (FQDN) of a Pod is set as hostname of its containers. 
  In Linux containers, this means setting the FQDN in the hostname field of the 
  kernel (the nodename field of struct utsname).  In Windows containers, this
  means setting the this means setting the registry value of hostname for the registry key HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters to FQDN.