but didn't get it how can I generate a custom app like "we create a simple window using java in windows like buttons and simple input area"
please guide me in this area also
If you're willing to put aside java for the minute and use Qt, there is support in goa for that. In the past I had pretty good success with the goa/Qt combination, but this was a while ago, I suspect things have only gotten better since as more features have been added to the Qt port.
Hope it helps
-CP