RSAKey key = new RSAKey(new Base64URL(n), new Base64URL(e), new Base64URL(d), KeyUse.SIGNATURE, null, new Algorithm(alg), kid, null, null, null);
Map<String, JWK> keys = Maps.newHashMap();
keys.put("client", key);
signingAndValidationService = new DefaultJwtSigningAndValidationService(keys);
signingAndValidationService.setDefaultSignerKeyId("client");
signingAndValidationService.setDefaultSigningAlgorithmName(alg);
urlBuilder.setSigningAndValidationService(signingAndValidationService);