Resource-Aware Structured Concurrency in Java 21 Shortened crosspost version of Part 5 from the "Structured Concurrency in Java (Java 21 Preview Edition)" series. Note This article uses Java 21 preview StructuredTaskScope APIs (JEP 453). API changes in later previews are covered in Part 9. Compile and run with --enable-preview . Originally published on engnotes.dev: Resource-Aware Structured Concurrency in Java 21 This is a shortened version with the same core code and takeaways. Virtual threads and structured scopes make concurrency easier to write. They do not make resource limits disappear. That is the part people forget. A service can look elegant in code and still overload a DB pool, exhaust HTTP connections, or push CPU saturation harder than it should. If there is no admission control, request fan-out can still hurt you.…