not null validation added

rest-api/src/main/java/lcsb/mapviewer/api/projects/models/functions/FunctionsController.java

@@ -30,8 +30,8 @@ public class FunctionsController extends BaseController {
   @GetMapping(value = "/{functionId}")
   public SbmlFunction getFunction(
       @PathVariable(value = "projectId") String projectId,
-      @PathVariable(value = "modelId") Integer modelId,
-      @PathVariable(value = "functionId") Integer functionId) throws QueryException {
+      @PathVariable(value = "modelId") int modelId,
+      @PathVariable(value = "functionId") int functionId) throws QueryException {
     return sbmlFunctionService.getFunctionById(projectId, modelId, functionId);
   }