address pr review

Author: keshavdandeva

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryJdbcOAuthUtility.java

@@ -684,13 +684,18 @@ private static GoogleCredentials getExternalAccountAuthCredentials(
       ExternalAccountCredentials credentials;
       if (credentialsPath != null) {
         try (InputStream stream = Files.newInputStream(Paths.get(credentialsPath))) {
-          credentials = ExternalAccountCredentials.fromStream(stream, httpTransportFactory);
+          credentials =
+              httpTransportFactory != null
+                  ? ExternalAccountCredentials.fromStream(stream, httpTransportFactory)
+                  : ExternalAccountCredentials.fromStream(stream);
         }
       } else if (jsonObject != null) {
+        InputStream stream =
+            new ByteArrayInputStream(jsonObject.toString().getBytes(StandardCharsets.UTF_8));
         credentials =
-            ExternalAccountCredentials.fromStream(
-                new ByteArrayInputStream(jsonObject.toString().getBytes(StandardCharsets.UTF_8)),
-                httpTransportFactory);
+            httpTransportFactory != null
+                ? ExternalAccountCredentials.fromStream(stream, httpTransportFactory)
+                : ExternalAccountCredentials.fromStream(stream);
       } else {
         IllegalArgumentException ex =
             new IllegalArgumentException("Insufficient info provided for external authentication");