code: private void preparePostHeader(HttpPost httpPost, String acceptMimeType, String contentMimeType) {
      if (acceptMimeType != null && !acceptMimeType.equals("")) {
        httpPost.setHeader(new BasicHeader("accept", acceptMimeType));
      }
      if (contentMimeType != null && !contentMimeType.equals("")) {
        httpPost.setHeader(new BasicHeader("Content-Type", contentMimeType));
      }
      httpPost.setHeader(new BasicHeader("project-id", projectId));
      if (token != null && bearerToken != null) {
        httpPost.setHeader(new BasicHeader("authorization", bearerToken.replaceAll("\"", "")));
      }
    }
docs: Add accept, content-type, projectId and token headers to an HttpPost object.
  
  @param httpPost
  @param acceptMimeType
  @param contentMimeType