MultiDataSet's getExampleMetaData() doesn't work

I created a MultiDataSet and set its meta data:

    MultiDataSet mds = new MultiDataSet(features, labels, featuresMask, labelMask);

But when I later retrieved the meta data via

    final MultiDataSet mds =;
    List<Serializable> multiDatasetList =  mds.getExampleMetaData();

the multiDataSetList was null. Why?

Can I use ExampleMetaData to store arbitrary info? If not, then I think MultiDataSet should have methods setUserData(Object obj) and getUserData().

(Sorry if this is the incorrect forum for discussion of nd4j.)

If I remember correctly, that is exactly how it is meant to be used.

And in principle there shouldn’t be anything that results it in being null as nothing special is done to the value you set there:

However, depending on what is going on in the code you didn’t share, it might get lost.

Because it isn’t a feature that is often used, I guess it is possible that some utility methods don’t take proper care of propagating the metadata.