voilà le résultat :

----------------------------------------------------------------------------------------------------------
Driver class = class org.postgresql.Driver v8.0
Prop name = PGDBNAME
Prop description = Database name to connect to; may be specified directly in the JDBC URL.
Prop value = null
Prop name = user
Prop description = Username to connect to the database as.
Prop value = null
Prop name = PGHOST
Prop description = Hostname of the PostgreSQL server; may be specified directly in the JDBC URL.
Prop value = null
Prop name = PGPORT
Prop description = Port number to connect to the PostgreSQL server on; may be specified directly in the JDBC URL.
Prop value = null
Prop name = password
Prop description = Password to use when authenticating.
Prop value = null
Prop name = protocolVersion
Prop description = Force use of a particular protocol version when connecting; if set, disables protocol version fallback.
Prop value = null
Prop name = ssl
Prop description = Control use of SSL; any nonnull value causes SSL to be required.
Prop value = null
Prop name = sslfactory
Prop description = Provide a SSLSocketFactory class when using SSL.
Prop value = null
Prop name = sslfactoryarg
Prop description = Argument forwarded to constructor of SSLSocketFactory class.
Prop value = null
Prop name = logLevel
Prop description = Control the driver's log verbosity: 0 is off, 1 is INFO, 2 is DEBUG.
Prop value = null
prop choice 0 = 0
prop choice 1 = 1
prop choice 2 = 2
Prop name = allowEncodingChanges
Prop description = Allow the user to change the client_encoding variable.
Prop value = null
Prop name = prepareThreshold
Prop description = Default statement prepare threshold (numeric).
Prop value = null
Prop name = charSet
Prop description = When connecting to a pre-7.3 server, the database encoding to assume is in use.
Prop value = null
Prop name = compatible
Prop description = Force compatibility of some features with an older version of the driver.
Prop value = null
prop choice 0 = 7.1
prop choice 1 = 7.2
prop choice 2 = 7.3
---------------------------------------------------------------------------------------------------------------

voici le code qui transforme mon tableau de byte en "fichier" :

-----------------------------------------------------
File generate = new File(dir + "/", nom);
generate.createNewFile();        
           
DataOutputStream out = new DataOutputStream(new FileOutputStream(generate));

out.write(docBytes);
out.close();
-----------------------------------------------------

Bonjour et merci de vous intéresser à mon problème.

@flo: je n'ai pas accès au lien que tu as donné.

Sinon la version de mon driver = postgresql-9.0-801.jdbc4.jar
et la version de la base = postgre 9.0

code avant la requete :
-----------------------------------------------------------------------------------------------
1- instanciation du driver = Class.forName("org.postgresql.Driver");

2- connection à la base = DriverManager.getConnection("proxool.consultation");
-----------------------------------------------------------------------------------------------

et au niveau de la recuperation :
-----------------------------------------------------------------------------------------
String requete = "SELECT NOM_DOCUMENT, DOC FROM " + TABLE_DOCS_ATTACHES + " WHERE " +
                        ID + " = " + id + " AND " +
                        DATE_FIN + " IS NULL;";

        GestionBd connexion = ConnexionPoolJDBC.getPoolConnexionJDBC().getConnexion(new Boolean(false),login);

        try {
            ResultSet resultat = connexion.executeRequete(requete);
            resultat.next();

            byte[] docBytes = resultat.getBytes("DOC");
}
---------------------------------------------------------------------------------------------------------

voila mais je suis pas sur que cela vienne du code.

Merci en tout cas de te pencher sur ça.

Julien