have you tried connecting with the arduino board from the computer via bluetooth to establish if the code is ok ?? Just use serial monitor - choose the right COM port and baud rate
that's the first thing you should do - if it works then there is something wrong with the android side of the project
have you got a datasheet of the BT module ?? I can't find it anywhere. My module doesn't require sending AT commands every time
ohh and I am affraid I can't help you as far as java is concerned - sorry