Bio4j - bioinformatics graph db


I just found about this database. I have no idea what it is but curious to know if anyone heard or used it and how does it compare to Cayley:

“Bio4j is a bioinformatics graph data platform, integrating most data available in Uniprot KB (SwissProt + Trembl), Gene Ontology (GO), UniRef (50,90,100), NCBI Taxonomy, and Expasy Enzyme DB.”