Hi
Before u start automation on Java application make sure that u installed Java Add-in for any testing tool ( say QTP Winrunner ). And set some properties for particular object before u automate...finally go for recording or any other method of scripting ( say descriptive ).
There is one more possibility that If u don't add properties of an object in repository( in QTP ) or GUI map file( in Winrunner ) then also it wil show error saying that object not found... So in this case make sure that ur object properties are there in repository/GUI map file.
Regards
Pavan