Make the geospatial extension (semi-)autoloadable for a Duckdb instance

[apano-on]

I use a Java application to generate custom SQL queries and send them to various databases including DuckDB (to a .db file). I pass as an argument the jdbc url as a string (required by the application). Based on tests with DuckDB spatial, for every jdbc connection the explicitly loaded extensions including DuckDB are unloaded (it seems to be the expected behavior), irrespective of where installed extension is saved.

However, at the moment I do not have a feature to append "LOAD spatial;" before the main query is run. The DuckDB jdbc driver url string does not seem to support initialization strings or scripts, it will instead create a new empty database.

Is there any workaround to skip the "LOAD spatial;" clause and make the extension persist for a custom db even after a connection is closed?