DisableHeadset.java

AudioManager audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
try {
    // setWiredDeviceConnectionState(int device, int state, String name);
    Method method = AudioManager.class.getMethod("setWiredDeviceConnectionState", int.class, int.class, String.class);
    method.invoke(audioManager, 4, 0, "headset");
} catch (Exception e) {
    e.printStackTrace();
}