ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired ORA-06512: at "APPS.WF_NOTIFICATION", line 5130 ORA-06512: at line 1

ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired ORA-06512: at "APPS.WF_NOTIFICATION", line 5130 ORA-06512: at line 1

Approve Workflow Notification Mailer --

ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired ORA-06512: at "APPS.WF_NOTIFICATION", line 5130 ORA-06512: at line 1

Solution :

1.
select do.owner,do.object_name,do.object_type,dl.session_id,vs.serial#, vs.program,vs.machine,vs.osuser
from dba_locks dl,dba_objects do,v$session vs
where do.object_name ='WF_NOTIFICATIONS' and do.object_type='TABLE' and dl.lock_id1 =do.object_id and vs.sid = dl.session_id;

Issue the command

sql > alter system kill sessions 'sid,serial#' immediate;

2. 
If you dont see anything in the query then there is some DML operation being performed in your system for the same process.

i.e.
1. Process A is running
2. Process A locked an Object.
3. Process B gets triggered.
4. Process B is blocked due to process A and throws the error.