How to parse captcha on android and then send a POST request with one connection?

Question

Java

Good day to all.
More recently, I figured out how to send a POST request from an android application using HttpUrlConnection.
Now you need to send the same request, but only with captcha, of course, while parsing it.
Well, it is logical that the captcha request and the request sending should be one connection.
Well, or somehow so that the relevant captcha is sent, and not from the previous request.
As I understand it, one HttpUrlConnection is not enough here.
PS I'm not doing anything illegal, I just want to send comments to the site through the android application.