org.zkoss.util.logging.hierarchy.disabled
From Documentation
Property:
org.zkoss.util.logging.hierarchy.disabled
Default: false [Since 5.0.9]
It disables the use of the hierarchy hierarchical .
Notice that this setting was introduced, because Googal App Engine doesn't allow java.util.logging.LogManager, which is required if the hierarchical logging is used. For more information, please refer to ZK Installation Guide: Google App Engine.