Index scan with like expressions

Hi everybody,

I'm having some trouble with index scan using like expressions, using
JDBC, but not in psql where the index is used.

Configuration and tables:
Postgres 8.1.4

My table "inscriptions":

Column | Type | Modifiers
------------------------+---------+-----------------------------------------------------------
id | integer | not null default
code | text | not null
beings_id | integer | not null
inscription_types_t_id | integer | not null
emitters_t_id | integer | not null
date_from | date |
date_to | date |
localizations_id | integer |
Indexes:
"inscriptions_pkey" PRIMARY KEY, btree (id)
"inscriptions_code_ikey" btree (code text_pattern_ops)

My query:
select beings_id from inscriptions
where code like '999999';

If I make an explain in psql:
QUERY
PLAN
-------------------------------------------------------------------------------------------
Index Scan using inscriptions_code_ikey on inscriptions
(cost=0.00..6.01 rows=1 width=4)
Index Cond: (code ~=~ '99999'::text)
Filter: (code ~~ '99999'::text)

If I do it from my java application with a parameter :
select beings_id from inscriptions
where code like ?;

2007-07-17 18:15:46,426 INFO [isoa.entities.bean.EntitiesApiBean]
EXPLAIN: Seq Scan on inscriptions (cost=100000000.00..100606290.60
rows=141577 width=4)
2007-07-17 18:15:46,426 INFO [isoa.entities.bean.EntitiesApiBean]
EXPLAIN: Filter: (code ~~ ($1)::text)

If I do it from my java application explicitly writing my code value
in the sql-string I get the correct plan.

I think I'm missing some important issue here, anyone can give me
a little help.

Thanks in advance
tonioc