Javadoc
Returns information about the set of variables or properties that can be resolved for the
given base object. One use for this method is to assist tools in auto-completion. The results
are collected from all component resolvers. The propertyResolved property of the ELContext is
not relevant to this method. The results of all ELResolvers are concatenated. The Iterator
returned is an iterator over the collection of FeatureDescriptor objects returned by the
iterators returned by each component resolver's getFeatureDescriptors method. If null is
returned by a resolver, it is skipped.