MTJ allows you to add mobile SDKs to Eclipse. One mobile SDK can contain one device platform, which can contain one or more devices. You can define these device platform's devices as the mobile runtimes used to develop MTJ applications for target mobile devices. After you have added the mobile SDK to MTJ, you must configure it in MTJ preferences. Every time you create an MTJ project, you are asked to select the mobile runtime for that project. The available mobile runtimes may include emulators and actual phone runtimes. The selection of available mobile runtimes depends on the chosen SDK.
With MTJ 0.7 version,you can choose which devices of the mobile SDK are imported in order to make them available for use in MTJ projects as the desired mobile runtime. You can define the device platforms in MTJ preferences.
Note: You can have multiple MTJ projects open at the same time, but one MTJ project can have only one active runtime platform at a time.