Random Forest FeatureImportance throwing NullPointerException

[Rachana Srivastava <Ra...@markmonitor.com>]

I have a Random forest model for which I am trying to get the featureImportance vector.

Map<Object,Object> categoricalFeaturesParam = new HashMap<>();
scala.collection.immutable.Map<Object,Object> categoricalFeatures =  (scala.collection.immutable.Map<Object,Object>)
scala.collection.immutable.Map$.MODULE$.apply(JavaConversions.mapAsScalaMap(categoricalFeaturesParam).toSeq());
int numberOfClasses =2;
RandomForestClassifier rfc = new RandomForestClassifier();
RandomForestClassificationModel rfm = RandomForestClassificationModel.fromOld(model, rfc, categoricalFeatures, numberOfClasses);
System.out.println(rfm.featureImportances());

When I run above code I found featureImportance as null.  Do I need to set anything in specific to get the feature importance for the random forest model.

Thanks,

Rachana