SQL & PL/SQL

I am just curious about the raise statement used in plsql.

exception
when others then
dbms_application_info.set_module('', '');
dbms_application_info.set_client_info('');
x_err_code := sqlcode;
x_err_message := sqlerrm;
log_message(p_message => x_err_message,
p_proc_name => lc_proc_name,
p_event_status => constants_pkg.event_error);
log_message('excpt5', lc_proc_name);
raise; ------------------------------------------------------------------------------------------------------------what does it do?it is not associated with any exception.
end apply_payment_by_vtxn;