---- Re-loader | Activator 3.4

Author: Tech‑Insights Blog
Date: April 2026


| Feature | What it does | Why you’ll love it | |---------|--------------|--------------------| | Dynamic Module Reloading | Reloads Java/Node/Python modules on‑the‑fly without restarting the host process. | Cuts down dev‑cycle from minutes to seconds. | | Hot‑Swap Dependency Injection | Swaps out service implementations at runtime using a lightweight DI container. | Enables A/B testing and rapid feature toggles. | | Live Config Reload | Watches config files (JSON, YAML, TOML) and pushes updates instantly. | No need to touch environment variables or restart containers. | | Zero‑Downtime Deployments | Combines graceful shutdown hooks with in‑process reloads. | Keeps SLA > 99.99% for critical services. | | Cross‑Platform CLI | ractl works on Windows, macOS, Linux, and within Docker containers. | Same commands everywhere—no platform gymnastics. | | Extensible Plugin System | Write plugins in any language that expose a reload() entry point. | Future‑proofs your stack. | ---- Re-loader Activator 3.4


+-------------------+       +-------------------+
|   Watcher Service | ----> |   Reload Engine   |
+-------------------+       +-------------------+
          ^                         |
          |                         v
+-------------------+       +-------------------+
|   Config Store    | <---- |   DI Container    |
+-------------------+       +-------------------+
          ^                         |
          |                         v
+-------------------+       +-------------------+
|  Application Core | <---- |   Plugin Manager  |
+-------------------+       +-------------------+

All components communicate via a lightweight internal event bus (based on EventEmitter for Node, java.util.concurrent.Flow for Java, and asyncio for Python). Author: Tech‑Insights Blog Date: April 2026


| Problem | Symptom | Fix | |---------|---------|-----| | File‑watch limit exceeded (Linux) | ENOSPC error, no reloads | Increase fs.inotify.max_user_watches (sysctl -w fs.inotify.max_user_watches=524288). | | Memory leak on repeated reloads | Process RAM climbs steadily | Ensure all resources (DB connections, thread pools) are closed in @PreDestroy/close() methods; use the StateBridge to pass references rather than recreating them. | | Circular dependency errors | RA throws CircularDependencyException | Refactor to break the cycle or mark one bean as @Lazy. | | Hot‑swap of native libraries fails | UnsatisfiedLinkError | Use the plugin manager to unload the native library first (ractl plugin unload <name>) before loading a new version. | | Config files not reloading | Changes ignored | Verify the config directory is part of the --watch set; check file permissions. | | Feature | What it does | Why