Error 400--Bad RequestFrom RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1 in EBS 12.2.4

APPLIES TO:

Oracle E-Business Suite Technology Stack - Version 12.2.4 and later
Information in this document applies to any platform.

SYMPTOMS

Users Encountering Error 400 Bad Request On Web Pages

From RFC 2068 Hypertext Transfer Protocol

10.4.1 400 Bad Request

The request could not be understood by the server due to malformed syntax.

The client SHOULD NOT repeat the request without modifications.

CAUSE

Applications File system out of sync

SOLUTION

Oracle suggested to follow below action plan but still issue not resolved.

1) Clear out cabo cache by doing the following:
A. Shutdown all services -

B. BACKUP the files in the following directories and then remove the files from the directories :
Note: Once you complete these steps, all the directories will still be present, but will be empty.
$OA_HTML/cabo/images/cache
$OA_HTML/cabo/styles/cache

Example:
cd $OA_HTML/cabo/images
cp -r cache cache_bkup
cd $OA_HTML/cabo/images/cache
rm -r *

C. Run the same steps for $OA_HTML/cabo/styles/cache

2) cd $FND_TOP/patch/115/bin
./ojspCompile.pl --compile --flush -p 2

3) Remove browser and Java Cache.

4) Restart services and retest.

Below solution resolved issue in my case.

There is a huge difference in the size of the two files _frameRedirect.class between working and non working environment, 

Seems like some class file corruption _cabo/_jsps 

Please perform the following: 

1) Take the backup of _pages/_cabo/_jsps directory in non working environment 
2) Copy this directory from working environment to non working environment 
3) Restart the services in target instance.

The issue was caused due to corruption of class file : _frameredirect.class