issue fixed when wodnloading file that didn't had a file defined

rest-api/src/main/java/lcsb/mapviewer/api/projects/overlays/OverlayController.java

@@ -144,12 +144,16 @@ public class OverlayController extends BaseController {
 
     FileEntry file = overlayRestImp.getOverlaySource(token, projectId, overlayId);
     MediaType type = MediaType.TEXT_PLAIN;
-    if (file.getOriginalFileName().endsWith("xml")) {
-      type = MediaType.APPLICATION_XML;
+    String filename = file.getOriginalFileName();
+    if (filename != null) {
+      if (file.getOriginalFileName().endsWith("xml")) {
+        type = MediaType.APPLICATION_XML;
+      }
+    } else {
+      filename = overlayId + ".txt";
     }
     return ResponseEntity.ok().contentLength(file.getFileContent().length).contentType(type)
-        .header("Content-Disposition", "attachment; filename=" + file.getOriginalFileName())
-        .body(file.getFileContent());
+        .header("Content-Disposition", "attachment; filename=" + filename).body(file.getFileContent());
   }
 
   /**