I created a test Library pointing to both DNA Components and Sequence Features, exported it to RDF, then imported the RDF file using SBOLutil.fromRDF and received an SBOLservice containing a null Library. The RDF file seemed to be fine, and when I commented out the instances of addFeature in my Library creation code everything worked. So it seems that SBOLutil.fromRDF can handle RDF files with Libraries that point to Sequence Features by way of DNA Components and Sequence Annotations, but not those with Libraries that point to Sequence Features directly.
I created a test Library pointing to both DNA Components and Sequence Features, exported it to RDF, then imported the RDF file using SBOLutil.fromRDF and received an SBOLservice containing a null Library. The RDF file seemed to be fine, and when I commented out the instances of addFeature in my Library creation code everything worked. So it seems that SBOLutil.fromRDF can handle RDF files with Libraries that point to Sequence Features by way of DNA Components and Sequence Annotations, but not those with Libraries that point to Sequence Features directly.