Jactl

Jactl scripting language mimics Virtual Threads on pre-Loom Java

The creator of Jactl, an embeddable scripting language for Java, explains how it was built to avoid blocking event-loop threads even though it targeted Java 8 and 11, long before Virtual Threads and Project Loom existed. Jactl uses an internal async mechanism that suspends a script's execution during blocking operations like database calls, freeing the underlying thread, and later resumes the script once the result is ready.