added java future for response handling

lib/codegen/java/async_http_client.dart

@@ -50,29 +50,20 @@ public class Main {
                 .setBody(bodyContent)\n
 ''';
 
-  final String kTemplateRequestEnd = """
+  final String kTemplateRequestEnd = '''
-                .build();
+            Future<Response> whenResponse = requestBuilder.execute();
-            ListenableFuture<Response> listenableFuture = asyncHttpClient.executeRequest(request);
+            Response response = whenResponse.get();
-            listenableFuture.addListener(() -> {
-                try {
-                    Response response = listenableFuture.get();
             InputStream is = response.getResponseBodyAsStream();
             BufferedReader br = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8));
             String respBody = br.lines().collect(Collectors.joining("\\n"));
             System.out.println(response.getStatusCode());
             System.out.println(respBody);
-                } catch (InterruptedException | ExecutionException e) {
-                    e.printStackTrace();
-                }
-            }, Executors.newCachedThreadPool());
-            listenableFuture.get();
         } catch (InterruptedException | ExecutionException | IOException ignored) {
 
         }
     }
-}
+}\n
-\n
+''';
-""";
 
   String? getCode(
     RequestModel requestModel,