Model schema = ModelFactory.createDefaultModel();
schema.add(A, RDFS.subClassOf, B);
schema.add(B, RDFS.subClassOf, C);
// create a fresh spec
OntModelSpec fixedSchemaSpec = new OntModelSpec( OntModelSpec.OWL_MEM );
// create a reasoner with a fixed schema and set the spec to use it
fixedSchemaSpec.setReasoner(PelletReasonerFactory.theInstance().create().bindFixedSchema(schema));
// create a new model whihc will have the schema loaded automatically
OntModel model = ModelFactory.createOntologyModel(fixedSchemaSpec);
PelletInfGraph graph = (PelletInfGraph) model.getGraph();