So, to your points specifically:
1) No. PhoneGap doesn't understand Java.
2) Not applicable; PhoneGap doesn't understand Java.
4) Server. PhoneGap isn't a server, and doesn't have a clue what to do with web.xml.
5) Not sure what you mean here. If you mean that you need to use AJAX to communicate with your backend, yes.
Without knowing more about your app and how it is structured, it's difficult to offer much more assistance.
So currently i am passing server Url into action of html file and it should remain in application itself but it is directly Redirecting to mobile browser with next page..
I have search on it and also tried plugins like inappbrowser and filetransfer but still it is redirecting outside application.
So neither InAppBrowser nor filetransfer will intercept anything on the action attribute. If you need to open a remote page, use the InAppBrowser API (more examples: Inappbrowser - Apache Cordova):
var ref = cordova.InAppBrowser.open('http://apache.org', '_blank', 'location=yes');