DarkSide SQL is a pure Java relational database server, derived from the discontinued Hypersonic SQL. It is SQL92 compliant and has a simple scripting language for writing server-side procedures. Clients can be written using a native JDBC driver or a similar C++ API. You can download the Windows Installer, source code and the client API using the links below. Please use 7-Zip to extract the files.
DarkSide SQL is not actively developed. I still respond to queries, bug reports and comments that I receive at vijay.the.schemer@gmail.com.
DarkSide SQL is distributed under the terms of GPLv3.