Auto Whitelist uses Java based technology, it uses the advanced NIO features of Java to provide fast performance. The filter will easily handle low to medium loaded mail servers. The current architecture is a single thread accepting connections, with children threads spawned for each incoming connection, which lasts only the duration of the connection. This design is sufficient for current needs. Future demand or user requests may result in it being increased.
All data is stored in a java properties file. Access to these files is synchronised to prevent corruption. If you run multiple versions of the daemon pointing to the same directory there will be corruption.