There are many tables and views in Oracle database that we can get information about with locked objects. You can access a lot of information from the following views.
Find locks in a table:
You can detect locks in a table with the following query.
SELECT B.Owner, B.Object_Name, A.Oracle_Username, A.OS_User_Name
FROM gv$Locked_Object A, All_Objects B
WHERE A.Object_ID = B.Object_ID