Kill a pending session on Oracle

I'm no DBA... so sometimes the simplest thing may be hard. I'm currently using Oracle in one of my projects, and I been having trouble with pending sessions / transactions. So I had to discover how to kill them. I found this link, which I reproduce partially here for the sake of preserving the information.

Identifying the locks:

SELECT  
 l.inst_id,  
 SUBSTR(l.oracle_username,1,8) ora_user,   
 SUBSTR(l.session_id,1,3) sid,  
 S.serial#,  
 SUBSTR(o.owner||'.'||o.OBJECT_NAME,1,40) object, 
 p.spid os_pid,  
 DECODE(l.locked_mode,
  0,'NONE',  
  1,'NULL',  
  2,'ROW SHARE',  
  3,'ROW EXCLUSIVE',  
  4,'SHARE',  
  5,'SHARE ROW EXCLUSIVE',  
  6,'EXCLUSIVE',  
  NULL) lock_mode  
FROM    
 sys.gv_$locked_object l, 
 dba_objects o, 
 sys.gv_$session s, 
 sys.gv_$process p  
WHERE
 l.OBJECT_ID = O.OBJECT_ID  
  AND     l.inst_id = s.inst_id  
  AND     l.session_id = s.sid  
  AND     s.inst_id = p.inst_id  
  AND     s.paddr = p.addr(+)  
ORDER BY l.inst_id

Killing the session:

The SID and the SERIAL# fields can then be used to issue the kill command:

ALTER SYSTEM KILL SESSION 'sid,serial#' IMMEDIATE