Corrected a problem where the version was null in the desktop version.

main/src/main/java/org/mobilitydata/gtfsvalidator/util/VersionResolver.java

@@ -5,8 +5,8 @@
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.SettableFuture;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
 import io.github.classgraph.ClassGraph;
 import io.github.classgraph.Resource;
 import io.github.classgraph.ScanResult;
@@ -151,19 +151,23 @@ private Optional<String> resolveLatestReleaseVersion(Optional<String> currentVer
             String.format(
                 "%s?application_type=%s&current_version=%s",
                 LATEST_RELEASE_VERSION_URL, applicationType, currentVersion.orElse("Ï")));
+    String jsonString = null;
     try (BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()))) {
-      Gson gson = new GsonBuilder().create();
-      VersionResponse response = gson.fromJson(in, VersionResponse.class);
-      if (response != null && !Strings.isNullOrEmpty(response.version)) {
-        logger.atInfo().log("resolved release version=%s", response.version);
-        return Optional.of(response.version);
+
+      // We expect the REST call to return something like :
+      // {"version":"1.4.0"}
+      jsonString = in.readLine();
+      if (Strings.isNullOrEmpty(jsonString)) {
+        return Optional.empty();
       }
+
+      JsonObject json = JsonParser.parseString(jsonString).getAsJsonObject();
+      String version = json.get("version").getAsString();
+      return Optional.of(version);
+    } catch (Exception e) {
+      logger.atInfo().log("error parsing response=%s", jsonString);
     }
-    return Optional.empty();
-  }
 
-  /** Serialization object for parsing the /version API response. */
-  class VersionResponse {
-    String version;
+    return Optional.empty();
   }
 }