jNetPcap 1.0 beta 1
jNetPcap is a Java wrapper around the Libpcap network packet capture library. The low-level API is exposed in Java, which allows kernel buffer tuning, flags, and other features. All captured packet buffers are wrapped, not copied, in efficient java.nio.ByteBuffer and delivered to Java by reference. This allows not-in-memory copies of packet data and very efficient and fast delivery of packets. The software is released for various platforms with the appropriate native library bundled.
URL: SourceForge.net: jNetPcap - Lib/WinPcap Java Wrapper