jNetPcap 1.2 will have Microsoft IpHelper API extensions. This extension allows retrieval of MAC address and also provides a number of other useful statistics and information about network interface not available from libpcap itself. The documentation is in javadoc that describes its usage.
PcapUtils contains a getHardwareAddress(String):byte[] method which abstracts the underlying details on how to retrieve a mac address on each platform using the extensions.
MS extension plans abandonded.
After careful consideration, this extension will not be release at this time. The code is currently working and its been tagged so that it can be always easily retrieved, but will not be released with any current release.
The reason from backing away from this extension is support. Although this may change in the future, currently there are no plans to release this extension.
The method PcapUtils.getHardwareAddress() will be released as originally planned, but implemented natively, behind the scenes, an not through this java extension.
Sly Technologies, Inc.
R&D