Last monday Oracle released JET version 2.0. The most important news in my opinion is that Oracle JET now is Open Source. Also Oracle JET is available on Github here .
There are a lot of new features added to 2.0. On this  site there’s an overview of the new features.
One nice feature is that you can generate a hybrid mobile application.
The installation of these tools can be done in the terminal:
npm –g install yo npm –g install grunt npm –g install cordova
After the installation of the components you can generate a mobile hybrid application. Enter in a terminal:
yo oraclejet:hybrid android_navbar --appName="android_navbar" --template=navBar --platforms=android
Change the directory in the terminal:
Then build the application with Grunt:
grunt build --platform=android
To run the application you can choose to run the application in the browser or in an Android emulator. I installed Android studio download here  and created a virtual device.
One remark: When you use an emulator make sure you installed in the SDK Manager Android 5.1.1 (version 22). This is required by Cordova .
Now you can run the application:
grunt serve --platform=android --destination=Nexus_5_API_23_x86