If an interface has both an "inet" and "inet6" entry, then getAdapter will retrieve the first entry that appears in the file. In the following example, the first entry for eth1 will retrieved. So swapping the order means the "inet" version of eth1 is retrieved. Is this intentional?
# This is an autoconfigured IPv6 interface
iface eth1 inet6 auto
# The primary network interface
auto eth1
iface eth1 inet static
address 192.168.0.15
netmask 255.255.255.0