Qt Jambi is the Qt library made available to Java. It is an open source technology aimed at all desktop programmers wanting to write rich GUI clients using the Java language, while at the same time taking advantage of Qt’s power and efficiency.
This system provides printed and cursive handwriting recognition service as a shared library on GNU/Linux/Unix systems.
Until someone writes another client, try the S/HIP:
https://sourceforge.net/projects/ship-project/
An academic project that grew greatly amongst all expectations: draughts server + client, using System V IPC API. Generic IPC classes (especially for message queues), widget-based UI (ncurses) can be reused in other projects.