Failed to use UI Framework module

Following steps closely on using UI Framework in your module , I configured things as required. Now I started following steps on UI Framework Step By Step Tutorial . I created a simple basic module but with just on demo page but when I try accessing it at https://localhost:8080/openmrs/uitestframework/demo.page I get the following error https://pastebin.com/Y1DYt7jD

Let someone help me out . cc @dkayiwa @darius @raff

Can you upload your module on github and i take a look?

Its here https://github.com/samuelmale/openmrs-module-uitestframework

The convention is that if you need to access demo.page, then you need a demo.gsp. I see that yours is demo.gsg

You will also need a DemoPageController.

That being said, going forward, we do not encourage using that ui framework for new development. Our recommended approach for doing user interfaces is found in the resources below: https://wiki.openmrs.org/display/docs/Open+Web+Apps+Module https://wiki.openmrs.org/display/docs/Open+Web+App+Development+Workflow https://wiki.openmrs.org/pages/viewpage.action?pageId=93359610

But why is the UI Framework discouraged for new dev. Is it considered obsolete?