Apply Application patch on Oracle Applications r12

We will use the Autopatch utility called adpatch:

1- Download the patch from Metalink.

2- Extract the patch: 
$ cd /u01/patches
$ unzip patchname.xp
This will create a directory with the same patchname. Change the owner of this directory
to be the application user:
$ chown -R applprod:oradba /u01/patches/patchname


3- Stop the application tier:

$ su - applprod
$ cd $ADMIN_SCRIPTS_HOME
$ adstpall.sh apps/apps

4- Enable the maintenance mode:
$ adadmin
Select [5] Chnge maitinance mode
Select [1] Enable maitinance mode

5- Move to the patch directory
$ cd /u01/patches/patchname

6- run the Autopatch utility
$ adpatch

7- After successful patching Disable the maintenance mode.
$ adadmin
Select [5] Change maintenance mode
Select [2] Disable maintenance mode

8- run the application tier back.
$ cd $ADMIN_SCRIPTS_HOME
$ adstrtal.sh apps/apps