Hi,
When you run the Android Simple Service (using the Java Language binding) application it is just a black display for the screen. When you run the Android Simple Client (using the Java Language binding) application it will show a spinner of trying to find a Simple Service then when connected disappear and shows a text box.
The Android emulator will not be able to communicate with the mobile device. You can only interact with other android applications loaded into the emulator itself. There is a limitation on the Android emulator around not having a bridged network connection, so it cannot send UDP packets out to the rest of the network or receive them.