Hermes FTP Server is a free, cross-platform FTP server adhering to RFC 959, RFC 2228, and RFC 2389. It is being developed in Java with a strong focus on security and extensibility.
Java Virtual System (JVS) is built around a virtual file system (VFS) - a common platform of Java, by Java, for Java. JVS extends JVM and makes it from an interpreter running half-compiled code a first-class server.