Analytical Java with DuckDB
Geertjan Wielenga will give a talk at J-Fall 2026, the Dutch Java conference organized by the NLJUG. The talk is scheduled for 4:55 PM CET on November 12, 2026, in Room 8. See the J-Fall timetable for the full program.
Venue
Pathé Ede, Laan der Verenigde Naties 150, 6716 JE Ede, The Netherlands.
Abstract
Your Java service just needs to answer a few analytical questions: top products this month, p95 latency per region, a quick join between a CSV export and a Parquet dump from the data team. The usual answers are to hammer your transactional database with GROUP BYs it was never designed for, ship the data off to a warehouse and wait, or write the aggregation by hand in streams. But did you know that there's another option that runs inside your JVM…
DuckDB is a free open source in-process analytical database: columnar, vectorized, zero infrastructure, and available to Java through a plain JDBC driver.
In this session, we'll use it to query Parquet, CSV, and JSON files directly, run analytical SQL over in-memory data, and push results straight into Java records and Apache Arrow.
Along the way, we'll look at where it beats a traditional RDBMS, where it doesn't, and how it fits into your services, batch jobs, tests, and CLIs… without any new operational setup or infrastructure.
