You don't need Google Glass for this course. You can build and publish Google Glass apps without Google Glass. For testing you can use Google Glass Emulator

The Glass Development Kit (GDK) is an add-on to the Android SDK that lets you build Glassware that runs directly on Glass.

When developing Glassware, the best practice is to develop with the Glass Development Kit. This allows you to access low-level hardware features and create robust experiences in a familiar Android environment.

The Glass Development Kit

The Glass Development Kit (GDK) is an add-on to the Android SDK that lets you build Glassware that runs directly on Glass. Use the GDK to take advantage of the following features:

1. Real-time User Interaction
2. Offline Functionality
3. Access to Hardware

Google designed the Glass platform to make the existing Android SDK just work on Glass. This lets you code in a familiar environment, but for a uniquely novel device.

The Mirror API

This RESTful API lets you build Glassware by letting you use the language of your choice and providing web-based APIs. You may want to use the Mirror API if you need:

1. Platform independence

2. Common infrastructure

3. Built-in functionality

Hybrid Glassware

Mirror API Glassware can invoke GDK Glassware through a menu item. You can use this hybrid model to leverage existing web properties that can launch fuller experiences that run directly on Glass.