ClassGraph vs Reflections vs Jandex in 2026: Picking a JVM Classpath Scanner That Still Works on Modern Java

Wed, 04 Nov 2026 00:00:00 +0000

You add one annotation — @Plugin, @Route, @Extension — and suddenly your framework needs to find every class that carries it. That is the moment a Java project discovers the classpath scanning problem: the JDK can tell you the superclass of a class you already have, but it cannot tell you “give me every class in this jar that implements Plugin”. You either scan, or you maintain a hand-written registry that drifts out of date the first time someone adds a module.

Classpath on Pi Stack

ClassGraph vs Reflections vs Jandex in 2026: Picking a JVM Classpath Scanner That Still Works on Modern Java