Http Parameters as Json

One of the requests on my page has some parameters and in Firefox DevTool it looks like:

How is it possible to create this structure in url or just add parameters in Java?

Usually I use Apache HttpPost and then:

 ArrayList<NameValuePair> postParameters;
  postParameters = new ArrayList<NameValuePair>();
  postParameters.add(new BasicNameValuePair("key", "value"));
  httpPost.setEntity(new UrlEncodedFormEntity(postParameters, "UTF-8"));

but have no idea how to pass json as my request parameter...