java.lang.IllegalArgumentException: URI with undefined scheme

Question

Good day. I've defined a 2 URI 's for a http call. The first one works great, the code is a complete copy beside some arguments. The second one throws a Exception . I'll list the code below.

public class WeatherAPI {
     
         private static String apiKey = "asdasd";
         private HttpResponse<String> response;
         private URI uri;
     
         private HttpRequest getRequest(URI newUri) {
             return HttpRequest.newBuilder()
                     .uri(newUri)
                     .build();
         }
     
         private HttpClient getClient() {
             return HttpClient.newBuilder().build();
         }
     
         private String getResponse(URI uri) {
             var client = getClient();
             var request = getRequest(uri);
             try {
                 response = client.send(request, HttpResponse.BodyHandlers.ofString());
             }  catch (IOException | InterruptedException e) {
                 e.printStackTrace();
             }
             return response.body();
         }
         public JSONObject getCityData(String lat, String lon) {
             String url = "api.openweathermap.org/data/2.5/weather"; //        System.out.println(uri);
             try {
                 uri = new URIBuilder(URI.create(url))
                         .addParameter("lat", lat)
                         .addParameter("lon", lon)
                         .addParameter("appid", apiKey)
                         .build();
                 System.out.println(uri);
     
             }  catch (URISyntaxException e) {
                 e.printStackTrace();
             }
             var body = getResponse(uri);
             System.out.println(body);
             return null;
         }
     
     }

Throws

Exception in thread "main" java.lang.IllegalArgumentException: URI with undefined scheme

Answer 1

It seems that the URL is missing the protocol-Prefix like http:// or https:// .. try

http: //api.openweathermap.org/data/2.5/weather

or

https: //api.openweathermap.org/data/2.5/weather

as URL. This should work.