JPSimulator is a debug tool allowing you to simulate several things in your game, helping you to test a language, an OS or a Client Type for instance, and let you see how your game behaves if it was executed on a specific device or in a particular configuration, without leaving ShiVa Editor.
The functions system.getOSType ( ), system.getOSLanguage ( ) or system.getClientType ( ) will return the simulated value instead of the real ones.
Here's a quick example to what can be done :
As you can see, this is ideal solution if you want to easily see how your game behaves with a different language or OS.
Other values can be simulated, like the screen resolution. Please refer to the API page for more details.