How to use sftp unattended?

[Lusiana]

Hi All,                                                               
                                                                      
I realise that similar topics has been discussed before,              
but I could not quite find a straight answer to it.                   
                                                                      
I'd like to create a java program that reads username and password    
from a source, then executes and drives sftp using the retrieved      
username and password.                                                
                                                                      
The bit that I'm having problem with is the supplying of password     
to ssh.                                                               
Is it by making ssh read the password from stdin?                     
How can this be done?                                                 
                                                                      
Any assistance will be appreciated.                                   
                                                                      
Thanks,                                                               
Lusiana