programming

20 Oct 2026

DZone Java Zone

Two Engines, One Query: DuckDB Inside Neo4j

If you've been following the database world lately, you'll have noticed DuckDB turning up in some unexpected places. One of the more interesting examples is pg_duckdb, a Postgres extension that embeds DuckDB directly into the Postgres process, letting analytical queries run through DuckDB's engine without leaving the database. It's a clever idea: keep your data where it is, but bring a faster analytical engine.

That got us wondering: could we do something similar with Neo4j?

20 Oct 2026 5:00pm GMT

Testing Java and Spring Applications With Kotlin: Low-Risk to Adoption

Teams considering or committed to adopting Kotlin often plan a migration as a series of rewrites, swapping Java services for Kotlin counterparts one microservice at a time. In practice, that kind of plan tends to stall before it produces any shipped code.

Kotlin's role in the JVM ecosystem is expanding because it doesn't require that kind of commitment. Companies such as Netflix, Adobe, and DoorDash have adopted it incrementally, alongside existing JVM systems, rather than through a full rewrite. The lowest-risk starting point is tests. They give you Kotlin's language benefits, including null-safety, data classes, and expressive lambdas, without touching anything that runs in production.

20 Oct 2026 2:09pm GMT

Java Virtual Threads Under Load: Three Production Limits

Virtual threads let us keep ordinary blocking code while many more requests wait concurrently. Under load, however, that brings three critical questions into focus:

How much work do we admit? Cheap threads can still build an expensive queue.
What belongs inside a lock? A sleeping lock holder still makes everyone else wait.
Who stops abandoned work? A caller's timeout does not cancel its task.

The examples below isolate these questions with separate before-and-after programs. Each program is complete: save its code block under the filename shown and run the accompanying command, without arguments. All you need is JDK 25. They use its compact source-file syntax, so no class declaration, build tool, external library, or preview flag is required.

20 Oct 2026 1:00pm GMT