code: public String postRequest(final URL url, final String jsonBody) throws MovieDbException {
          try {
              HttpPost httpPost = new HttpPost(url.toURI());
              httpPost.addHeader(HTTP.CONTENT_TYPE, APPLICATION_JSON);
              httpPost.addHeader(HttpHeaders.ACCEPT, APPLICATION_JSON);
              StringEntity params = new StringEntity(jsonBody, ContentType.APPLICATION_JSON);
              httpPost.setEntity(params);
  
              return validateResponse(DigestedResponseReader.postContent(httpClient, httpPost, CHARSET), url);
          } catch (URISyntaxException | IOException ex) {
              throw new MovieDbException(ApiExceptionType.CONNECTION_ERROR, null, url, ex);
          }
      }
docs: POST content to the URL with the specified body
  
  @param url URL to use in the request
  @param jsonBody Body to use in the request
  @return String content
  @throws MovieDbException exception