あまり使う機会は無いけど。

try {
    FileInputStream fin = new FileInputStream(new File("sparql.json"));
    ResultSet result = JSONInput.fromJSON(fin);
    while(result.hasNext()) {
        QuerySolution qsol = result.next();
        Literal literal = qsol.getLiteral("o");
        String str = (String) literal.getValue();
        System.out.println(str);
    }
 } catch (FileNotFoundException e) {
 e.printStackTrace();
 }