JCR Observation's a way to listen on persistence changes of a Repository. It provides several options to configure the listener for an interesting only changes. To use properly, it's important to understand concept of events filtering for a registered EventListener (8.3.3 Observation Manager). An often confusing part, it's the absPath, it's an associated parent of a location you want to observe events on. I.e. it's a parent of child node(s) or this parent property(ies); if isDeep is true then you'll get events of all the subtree of child nodes also. The same actual for uuid and nodeTypeName parameters of ObservationManager.addEventListener() method.