Receive simultaneous notifications for multiple characteristics from a single server

Question

I am trying to reproduce an Android app project without much Android development or Bluetooth experience. In the code, the original author collected data from two characteristics (coming from a single service) to plot them in real time. In the original code, the author uses the following code excerpt to establish the characteristics notifications and get both data.

        @Override
        public void onServicesDiscovered (BluetoothGatt gatt, int status){
            BluetoothGattService handservice=gatt.getService(handserviceuuic);
            BluetoothGattCharacteristic plethchar=handservice.getCharacteristic(handcharuuic);
            BluetoothGattCharacteristic pulsechar=handservice.getCharacteristic(pulseuuic);
            gatt.setCharacteristicNotification(plethchar,true);
            gatt.setCharacteristicNotification(pulsechar,true);
        }
        @Override
        public void onCharacteristicChanged (BluetoothGatt gatt, BluetoothGattCharacteristic characteristic{
            byte[] reading=characteristic.getValue();
            if(startbutton.isChecked()==true){
                if(characteristic.getUuid().toString().equals("ec0a883a-4d24-11e7-b114-b2f933d5fe66")){
                    plethprocessingfoot(reading);
                }
                else{
                    pulseprocessingfoot(reading);
                }
            }
        }

When I apply this code on my phone, I only get notified of the first characteristic because the only UUID that gets returned by characteristic.getUuid() is the one for the first characteristic. If I comment out the code for the first characteristic, then I can get notified on the second characteristic just fine. How can I change this code so that I get notified of both characteristics?