It would be nice to know if anybody else can make the plugin to work and
find it useful.
The plugin itself does not yet have new features added or bugs fixed
when compared with the previous 5 years old 1.3 version. The most
important difference is that the plugin now works again and it has some
documentation. However, the SpatiaLite binaries have been upgraded from
1.0 to 4.2.1-RC1 which does mean a lot and all these SpatiaLite
functions https://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html are now available for OpenJUMP users also through this plugin. The DB
Query Plugin has been able to use the newest binaries (mod_spatialite)
for some time already but without a GUI.
I am planning to make a little bit polished 1.5 version but I know that
with my skills it won’t include any major improvements. I have been able
to localize a few things which should be fixed or improved in the java
code and I would be happy to point them to voluntary fixers.