code: public static KeyPair buildRSAKeyPairFromJwk(final String json) {
          CommonHelper.assertNotBlank("json", json);
  
          try {
              final RSAKey rsaKey = RSAKey.parse(json);
              return rsaKey.toKeyPair();
          } catch (final JOSEException | ParseException e) {
              throw new TechnicalException(e);
          }
      }
docs: Build the RSA key pair from the JWK JSON.
  
  @param json the json
  @return the key pair