URL url;

url = new URL ("http://localhost:8080/jsonrpc");
HttpURLConnection conn = (HttpURLConnection)url.openConnection();

conn.setRequestMethod("POST");
conn.setDoInput (true);
conn.setDoOutput (true);
conn.setUseCaches (false);
conn.setRequestProperty("Content-Type", "application/json");

//DataOutputStream dataOutputStream = new DataOutputStream(conn.getOutputStream());
//BufferedWriter test = new BufferedWriter(dataOutputStream);

PrintWriter out = new PrintWriter(conn.getOutputStream());

String content = "{\"jsonrpc\": \"2.0\", \"method\": \"JSONRPC.Introspect\", \"id\": 1}";
content = content.trim();
System.out.println(content);

BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));


//out.write("{\"jsonrpc\": \"2.0\", \"method\": \"JSONRPC.Introspect\", \"id\": 1}");
//out.flush();
out.print("{\"jsonrpc\": \"2.0\", \"method\": \"JSONRPC.Introspect\", \"id\": 1}");
out.flush();
out.close();

// Get response data.
String str;
while (null != ((str = in.readLine()))){
    System.out.println (str);
}
in.close ();