diff --git a/README.md b/README.md index fc7b2885..274d0828 100644 --- a/README.md +++ b/README.md @@ -268,13 +268,15 @@ from Oracle. Because the `ImageIO` plugin registry (the `IIORegistry`) is "VM global", it doesn't by default work well with servlet contexts. This is especially evident if you load plugins from the `WEB-INF/lib` or `classes` folder. +Unless you add `ImageIO.scanForPlugins()` somewhere in your code, the plugins might never be available at all. -Servlet contexts dynamically loads and unloads classes (using a new class loader per context). +I addition, servlet contexts dynamically loads and unloads classes (using a new class loader per context). If you restart your application, old classes will by default remain in memory forever (because the next time `scanForPlugins` is called, it's another `ClassLoader` that scans/loads classes, and thus they will be new instances in the registry). -To work around this resource leak, it is recommended to use the `IIOProviderContextListener` that implements +To work around both the discovery problem and the resource leak, +it is recommended to use the `IIOProviderContextListener` that implements dynamic loading and unloading of ImageIO plugins for web applications.