GlideApp symbol not found in Android Studio 4.1 - android-glide

Question

I have been using Glide 4.11.0 and Realm 6.0.2 for some time now, and recently upgraded Android Studio 4.0.x to 4.1. All has been going fine. Today I ran the lint checker, and started doing some "clean up", nothing out of the ordinary (it would seem). One of the things I did a lot of was to replace switch statements that were testing against R.id. with if-else statements per the lint warning about what's gonna happen in Gradle 5.0.
When I did this, I did use a number of int variables I named 'id' that were to replace the value to compare - i.e. instead of a switch statement that would be:
switch (menuOpt.getId()) {
case R.id.xxx:
...
}
I would do:
int id = menuOpt.getId();
if ( id == R.id.XXX) {
} else if....
per the new guidelines.
Suddenly, on a full build AS complains that it no longer recognizes GlideApp, and I am also getting a very weird message about Realm not being able to process correctly:
C:\BLD\AndroidStudioProjects\InTouch\app\src\main\java\com\reddragon\intouch\ui\MediaPlayerActivity.java:61: error: cannot find symbol
import com.reddragon.intouch.utils.GlideApp;
^
symbol: class GlideApp
location: package com.reddragon.intouch.utils
C:\BLD\AndroidStudioProjects\InTouch\app\src\main\java\com\reddragon\intouch\ui\MediaDialogActivity.java:92: error: cannot find symbol
import com.reddragon.intouch.utils.GlideApp;
^
symbol: class GlideApp
location: package com.reddragon.intouch.utils
C:\BLD\AndroidStudioProjects\InTouch\app\src\main\java\com\reddragon\intouch\ui\MediaListActivity.java:48: error: cannot find symbol
import com.reddragon.intouch.utils.GlideApp;
^
symbol: class GlideApp
location: package com.reddragon.intouch.utils
Note: Version 10.0.0 of Realm is now available: https://static.realm.io/downloads/java/latest
Note: Processing class Album
error: Class "Album" contains illegal final field "id".
Note: [1] Wrote GeneratedAppGlideModule with: []
Class "Album" contains illegal final field "id".
4 errors
I have had the field 'id' in my Album class for about 2 years with no issues!
No manner of rebuild, invalidating cache and restarting, syncing gradle files or "reload all from disk" seems to help.
Actually, if I invalidate and restart, I don't get the red squiggle in the offending classes that are referencing GlideApp, but as soon as I start to run the app and it goes through a build process it errors out.
I Googled a bit and found one post where there seemed to be some conflict between Realm and Glide (RequestOptions), but the strange thing to me is why would this suddenly start occurring?
I have validated that the GlideAppjava class is in fact getting built - I am using the debug build variant, and I can see in the file system GlideApp.java that is in the ap_generated_sources/debug directory in the proper package where I have my class that extends AppGlideModule with the #GlideModule annotation.
So GlideApp is getting generated. It just isn't getting recognized.
One of the other new things is that I've recently created a Dynamic Feature module. This module does depend on a class that is in the base module (where GlideApp is referenced). Not sure if this is relevant (I had many, many successful builds before I started doing lint clean-up).
So frustrating! Any help appreciated.

Answer 1

It turns out that the answer was staring right at me, although somewhat hidden: part of the lint check that I did was accept some suggestions about making variables 'final' - including those that are used in Realm classes to define Realm objects. Realm doesn't like that - above build error output includes as a last line the statement 'Class "Album" contains illegal final field "id".'
"Album" extends RealmObject, and the "auto accept" of the lint's suggestion to make some of the fields final was the culprit.
I think this issue with Realm caused a ripple effect somehow with the other annotation processing - when I went back to all the RealmObject classes and removed the "final" declaration, build now completes smoothly.