Architecture
How AEM works internally, explained for engineers who need to debug it.
How an AEM Maven Project Actually Builds a Deployable Package
How the parent pom.xml and the core, ui.apps, ui.content, ui.config, and all modules of an AEM project combine to produce a single deployable package, and why the all module is the real deployment unit.
Why Your Java Class Can't See That Other Class: OSGi Bundle Classloading in AEM
Why a class that compiles fine in Maven can still throw ClassNotFoundException in AEM, how Import-Package/Export-Package control bundle visibility, and how to debug it with the Felix web console.