You now can use : okhttp3.FormBody instead of FormEncodingBuilder.
Edit :
Something like this
OkHttpClient client = new OkHttpClient();
FormBody body = new FormBody.Builder()
.add("your_param_1", "your_value_1")
.add("your_param_2", "your_value_2")
.build();
Request request = new Request.Builder()
.url("http://my.wonderfull.url/to/post")
.post(body)
.build();
Response response = client.newCall(request).execute();
If you want to post JSON content replace the FromBody by a RequestBody:
RequestBody body = RequestBody.create( JSON, json );
Edit 2:
The URL to use is (this one is mine):
https://docs.google.com/forms/d/1k96sccTC_24b6jo9Fs4h_ML-FVKHCMElgjUzOwSkwu4/formResponse
And you also have to find the name of your form inputs by looking at the source code of the form, the name starts with entry. following by a number:
<input name="entry.361168075" value="" class="ss ......
So your formBody looks like this:
FormBody body = new FormBody.Builder()
.add( "entry.361168075", "Red" )
.build();
I made up a full workable example there :
http://blog.quidquid.fr/2016/01/post-from-java-to-a-google-docs-form/