If you are looking for a very good toolkit for data-centric (and other) application development, with form editor, report writer, SQL generator based on properties imported from the database (but also capability to use "manual" SQL or CLI calls), dynamic 4GL, C and Java integration, capability of n-tier development with both client and server side developed in the same tool (or not), text, GUI and Web deployment etc, look at https://sourceforge.net/projects/possl/
. What sets this tool aside is tremendous productivity it affords.
This is essentially the version 4.18 or Prolific's Panther tool (http://www.prolifics.com/specialties/prolifics_accelerators/jampanther
, now in version 5.5), with very permissive license akin to Apache, BSD or "Artistic" (as opposed to GPL). The toolset has 25+ years of history behind it, and I can wholeheartedly recommend it (although I mostly use the commercial version, because my clients do).
I suggested early on to GNUe team to adopt and further develop this toolset, forking it if they see it fit, and concentrate their efforts on developing the actual ERP instead of reinventing the toolset wheel, but nobody was interested, apparently because of the tool commercial origin. I suppose they don't use Java or Eclipse, either, then... This is all too common OSS malady - reinventing everything, instead of building on efforts of others.
I hope someone will find this useful.