Overview of ADF Mobile

ADF Mobile provides a way of quickly developing on-device applications for Android and iOS. Following is some knowledge about overview of the ADF Mobile technology. 
Three Types of mobile application
Native apps are built for a specific platform with the platform SDK, tools and languages, typically provided by the platform vendor (e.g. xCode/Objective-C for iOS, Eclipse/Java for Android, Visual Studio/C# for Windows Phone).
Mobile Web apps are server-side apps, built with any server-side technology (PHP, Node.js, ASP.NET) that render HTML that has been styled so that it renders well on a device form factor.
Hybrid apps, like native apps, run on the device, and are written with web technologies (HTML5, CSS and JavaScript). Hybrid apps run inside a native container, and leverage the device’s browser engine (but not the browser) to render the HTML and process the JavaScript locally.
What is Oracle ADF Mobile
Oracle ADF Mobile is a hybird framwork for mobile development. Enables development of a single source and generation of native applications for both iOS and Android devices. Coding of logic is done with the Java language. UI layer can be developed with a set of components (AMX) that generate an HTML5 based user interface. In addition Oracle ADF Mobile can incorporate local HTML5 pages and remote HTML content generated from other servers.
So, you need noticed following point.
   Java - Application logic is developed with the Java language.
   Hybrid UI Approach - For the UI developers can mix and match three approaches:Use the declarative HTML5 components provided with the framework, which provides all the normal input and layout controls you expect and also add charts/maps/gauges along with it to provide a very comprehensive UI controls.
Use other HTML5 framework like JQuery
Include content generated on remote servers – for example JSF content
   Device Feture Access - Oracle ADF simplifies access to device services such as Camera, SMS, locations, contacts and more with a simple drag and drop creation of interaction.
   Secure – ADF Mobile provides integrated security that works with your server back-end as well. Whether you’re using remote URLs, local HTML or AMX, you can secure any/all of your features with a single consistent login page. Since we also give you SQLite encryption, we are assured that your data is safe.
   Productive - Focused on a visual and declarative development approach, Oracle ADF Mobile extends the development experience provided by Oracle ADF from Web to Mobile devices. 

ADF Mobile Architecture

What is PhoneGap does here is?

About Hybird application(Web-based native apps), which has three common framwork:Titanium, PhoneGap, ADF Mobile.ADF Mobile is based party of PhoneGap, and allow you to create a "native" application using only HTML5 and JavaScript,and is a new component-driven framework:ADF Mobile AMX files.
PhoneGap will convert the web based application(developed with HTML5,CSS&JQueryMobile) into a native iOS, Android,Blackberry,Windows Phone, Plam OS and Symbian kind of an application.
Therefore, the end-user will use the app not as a web based app(meaning,not in a web browser),but as a native app.
Key benefits and features of Oracle ADF Mobile for developing hybrid mobile applications across multiple device platforms.
About Oracle ADF Mobile Demo for Developing hybrid Mobile Applications, you can refer to
http://www.youtube.com/watch?v=XWyPP55dZLU

There is a video about Overview of ADF Mobile.