Getting ORA-04021 when running grant execute on package?

If you are trying to grant execute on a package and getting ORA-04021 'timeout occurred while
waiting to lock object' try the following:

Check who else is using the packages:

SQL> select * from v$access where object = 'PACKAGE_NAME';

If you see another session accessing the package ask the user to logout or kill them.
Alternatively you can try:

SQL> alter system flush shared_pool;