An emulator platform simulates the execution of an application on one or more target devices. For example, the Java ME SDK enables you to run applications on several example devices, or "skins" included with the emulator. An emulator allows you to understand the user experience for an application on a particular device, and to test the portability of the application across different devices.
In the IDE, you specify the emulator platform as part of the overall project configuration. Many emulator platforms are packaged as software developer kits (SDKs) from manufacturers of mobile devices.
Some of the differences between emulators include their support for:
You can access the special tools and extensions of an emulator platform by choosing the Tools and Extensions tab in the Java Platform Manager.
Note that having an emulator does not completely free you from testing on your target devices. An emulator can only approximate a device's user interface, functionality, and performance. For example, an emulator might not simulate processing speed, so an application may run faster or slower on a target device than it does on an emulator.