Java Database Connectivity (JDBC)

I have a problem with inserting and updating database in postgresdatabase.
When I do something with database using PreparedStatement every string has trailing spaces at the end. How to avoid this situation?
Example:

PreparedStatement p = con.prepareStatement("insert into hospital_user (login, callmanager_user, pin, css, user_type_id, surname, name, phone) values (?, ?, ?, ?, ?, ?, ?, ?)");
p.setString(1, this.login);
p.setString(2, this.callmanagerUser);
p.setInt(3, this.pin);
p.setString(4, this.css);
p.setInt(5, this.userTypeId);
p.setString(6, this.surname);
p.setString(7, this.name);
p.setInt(8, this.phone);
if (1 == p.executeUpdate()) {
return "ok";
}

althoug this.login = 'foo' it is inserted as 'foo ' (trailing spaces at the end) if login is defined in DB as varchar(20) I have foo with 17 spaces at the end.
I use Postgres 7.4 and JDBC postgresql-8.2-504.jdbc3.jar

Any ideas hov to trim this spaces?