connect to remote db

hi,

I want to connect to database repl_isar located in host isar from host
willy. So I wrote:

String url = "jdbc:postgresql://isar/repl_isar";
conn = DriverManager.getConnection(url,username,password);

But it fails by given error both in postmaster running repl_isar and local
site willy.

java.sql.SQLException: User authentication failed

If I tried local database url="repl_willy", the same username and password
work well.

I did run "createuser" script and even run SQL "create user ..".

What do I missed?

Thanks,

Yi Lin