Possible changes 

Possibilities for discussion.

1. Quads are not extended Triples (useful if the default graph is a union of named graphs but this isn't always the case) but share a common supertype.
1.  Add a CONTRIBUTING file
1.  3 parts of a Literal
1.  getObject is a Resource, not a Literal
Java places certain requirements on `.equals` for the collections.  I think appealing to custom comparators is better done for special situations, not the general case.  An RDF graph is a set of triples. The quality relationship here must be structural equality,

> Would I be able to compare TermTuple-s from Jena and Sesame?

That's an implementation issue (this is an interface!) but from an RDF point of view, yes. Whether we want the interface to make that part of the contract, or whether it would restrict implementation possibilities is a matter to discuss.

`Triple.equals` is `subject.equals && predicate.equals && object.equals`