Getting NPE in ReadRequest on BleReadCallback

[ivbabar]

I'm using this code to read firmware version of the connected BLE device and I doubt this code is causing this exception

    ```
Ble.getInstance().read(Ble.getInstance().getBleDevice(0), new BleReadCallback<BleDevice>() {
                    @Override
                    public void onReadSuccess(BluetoothGattCharacteristic characteristic) {

                        if (characteristic != null || characteristic.getStringValue(0) != null) {
                            fwVersion = characteristic.getStringValue(0);
                            Log.d(TAG, "Remote controller firmware version: " + fwVersion);
                        }

//                        locker.release();
                    }
                });

Here is the exception i'm getting on Crashlytic

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'void cn.com.heaton.blelibrary.ble.callback.BleReadCallback.onReadSuccess(android.bluetooth.BluetoothGattCharacteristic)' on a null object reference
       at cn.com.heaton.blelibrary.ble.request.ReadRequest.handleMessage(ReadRequest.java:44)
       at cn.com.heaton.blelibrary.ble.BleHandler.handleMessage(BleHandler.java:48)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loopOnce(Looper.java:226)
       at android.os.Looper.loop(Looper.java:313)
       at android.app.ActivityThread.main(ActivityThread.java:8680)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:571)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1135)