convert 'foobar'::text to the string foobar

Hello,

I want to retrieve the default value of a TEXT column of a table.
So far, I had a hard time writing this query and after looking at
postgresql doc I have looked in phppgadmin source code, and am
finally using:

   SELECT adef.adsrc AS value
     FROM pg_catalog.pg_attribute a
     LEFT JOIN pg_catalog.pg_attrdef adef
            ON a.attrelid = adef.adrelid
           AND a.attnum = adef.adnum
    WHERE a.attrelid = (SELECT oid FROM pg_catalog.pg_class WHERE relname = ?)
      AND a.attname = ?

when used with a table with a default value set by:

ALTER TABLE table_name ALTER COLUMN column_name SET DEFAULT 'foobar';

displaying that way with \d:

 column_name   | text                   | not null default 'foobar'::text

retrieved as a String in Java, I end up with "'foobar'::text"
where I'd need just the string "foobar" (without any quote).

Is there something I'm doing wrong?

Thank you.

--
Guillaume Cottenceau