It only shown one single problem: inclusion of an unrealistic but very populistic goal of creating an automatic migration between different database engines (i.e., something that automagically could take your carefully hand-crafter HSQLDB, and turn it into an identically behaving Firebird) has devastating effect on the project. When the task of implementing the FB support, the only reasonable goal of that project, was done, the other task - the migration wizard - was implemented somehow. When FB got out of experimental stage, the only thing that was too problematic was exactly that wizard - and that wizard had forced making FB - as a whole!!! - back experimental. A whole disaster.
Is there any real-world tool capable to migrate between different DBMSs lossless? We needed to focus on introduction of FB as the new default engine; then - if desired - moving HSQLDB to extension, for people still wanting to use those DBs (or, maybe, just continue supporting HSQLDB as a legacy - which at that stage would not mean dependency on Java (in this specific area), because we provided a Java-less default alternative). And that would make the project successful years ago. But - there is marketing. There is that “kill Java with fire”, which doesn’t want to stop anywhere except total extermination…