EBS 12.2 -- custom OAF Deployment doesn't realize the new code -- due to misplaced files/codes under OA_HTML

We had an issue with the custom OAF deployment in an newly upgraded EBS 12.2.10 environment.

We just couldn't make the new codes be activated and no matter what we did, the application was still using the old codes and we were not able to deploy the changed OAFs.

Actually, our deployments were fine, but the changes that were supposed to be delivered with those deployment, were not reflected to the system. 

Even when we deleted a custom code from JAVA_TOP, the page that was related with that code was still working without any problems.. So it was a clue.. That is, somehow EBS was getting the code from elsewhere.. Note that, we were facing this issue for almost all custom developments under JAVA_TOP. 

Before finding the real cause, we did the following, but didn't help;

Stopped all the application services, recompiled JSPs, started the application services

Cleared the java cache using Functional administrator

Cleared the browser cache

Cheared any networking cache ( including the Load Balancer)

Then, we saw that there were 2625 classes in the directory named $OA_HTML/WEB-INF/oracle.

The custom classes were also there..

So, we removed; any code (except for _pages) that reside in the directory named $OA_HTML/WEB-INF/oracle; and the issue disappeared.. 

As you may guess; the real cause was the misplacement of code.. 

That is, when the custom classes are deployed to OA_HTML/WEB-INF/oracle, they take precedence over customall,jar generated by adcgnjar under $JAVA_TOP. 

So no matter what we deploy to JAVA_TOP, it doesn't matter.. I mean, if the code we deploy to JAVA_TOP exists in OA_HTML/WEB-INF/oracle then, the code that resides in OA_HTML/WEB-INF/oracle is executed. So we can't see our changes, we can't activate our changes..

That was an interesting issue, and the question "who put the codes there?" -> is still a mystery :)