import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
public static void main(String[] args) throws Exception {
String targetUrl = "http://api.solapi.com/messages/v4/groups/G4V20180307105937AAAAAASCHEDULED/schedule";
String parameters = "{\"scheduledDate\":\"2021-11-16T05:12:39.157Z\"}";
URL url = new URL(targetUrl);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("POST");
con.setRequestProperty("Content-Type", "application/json");
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(parameters);
int responseCode = con.getResponseCode();
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBuffer response = new StringBuffer();
while ((line = in.readLine()) != null) {
System.out.println("HTTP response code : " + responseCode);
System.out.println("HTTP body : " + response.toString());