The posix library is dedicated to implementing posix functionality which
is dependent on C calls via native code or specific file formats.

Additional functionality proposed:

Group class	similar to Passwd.

Unix domain sockets.  Difficult to integrate with java.net for Datagrams.
May have to duplicate java.net functionality.  Will be easier for Java 2.

Attaching a Socket to an open file descriptor.  Some unix APIs pass 
sockets to a process via open file descriptors - e.g. inetd and AIX SRC.
Can this be done portably?

Functionality best implemented elsewhere:

Syslog	implemented via Pure Java in other packages.