Statement st1 = vf.createStatement(uri1, uri2, plainLit);
ByteArrayOutputStream out = new ByteArrayOutputStream();
RDFWriter rdfWriter = rdfWriterFactory.getWriter(out);
rdfWriter.getWriterConfig().set(JSONLDSettings.JSONLD_MODE, JSONLDMode.COMPACT);
rdfWriter.handleNamespace("ex", exNs);
rdfWriter.startRDF();
rdfWriter.handleStatement(st1);
rdfWriter.endRDF();
ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());