#vulnerable code 
                                @Override
    public void onFirstRow (final int index, final ButtonEvent event)
    {
        if (event == ButtonEvent.DOWN)
            return;

        final CursorDeviceProxy cd = this.model.getCursorDevice ();

        final ModeManager modeManager = this.surface.getModeManager ();
        if (event == ButtonEvent.UP)
        {
            if (!cd.hasSelectedDevice ())
                return;

            if (!this.showDevices)
            {
                cd.setSelectedParameterPageInBank (index);
                return;
            }

            if (cd.getPositionInBank () != index)
            {
                cd.selectSibling (index);
                return;
            }

            final boolean isContainer = cd.hasLayers ();
            if (!isContainer)
            {
                ((DeviceParamsMode) modeManager.getMode (Modes.MODE_DEVICE_PARAMS)).setShowDevices (false);
                return;
            }

            final ChannelData layer = cd.getSelectedLayerOrDrumPad ();
            if (layer == null)
                cd.selectLayerOrDrumPad (0);
            modeManager.setActiveMode (Modes.MODE_DEVICE_LAYER);
            return;
        }

        // LONG press - move upwards

        this.surface.setButtonConsumed (PushControlSurface.PUSH_BUTTON_ROW1_1 + index);

        // There is no device on the track move upwards to the track view
        if (!cd.hasSelectedDevice ())
        {
            this.surface.getViewManager ().getActiveView ().executeTriggerCommand (Commands.COMMAND_TRACK, ButtonEvent.DOWN);
            return;
        }

        // Parameter banks are shown -> show devices
        final DeviceParamsMode deviceParamsMode = (DeviceParamsMode) modeManager.getMode (Modes.MODE_DEVICE_PARAMS);
        if (!deviceParamsMode.isShowDevices ())
        {
            deviceParamsMode.setShowDevices (true);
            return;
        }

        // Devices are shown, if nested show the layers otherwise move up to the tracks
        if (cd.isNested ())
        {
            cd.selectParent ();
            modeManager.setActiveMode (Modes.MODE_DEVICE_LAYER);
            deviceParamsMode.setShowDevices (false);
            cd.selectChannel ();
            return;
        }

        // Move up to the track
        this.surface.getViewManager ().getActiveView ().executeTriggerCommand (Commands.COMMAND_TRACK, ButtonEvent.DOWN);
    } 
                            #location 48 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public void onFirstRow (final int index, final ButtonEvent event)
    {
        if (event == ButtonEvent.DOWN)
            return;

        if (event == ButtonEvent.UP)
        {
            final CursorDeviceProxy cd = this.model.getCursorDevice ();
            if (!cd.hasSelectedDevice ())
                return;

            if (!this.showDevices)
            {
                cd.setSelectedParameterPageInBank (index);
                return;
            }

            if (cd.getPositionInBank () != index)
            {
                cd.selectSibling (index);
                return;
            }

            final ModeManager modeManager = this.surface.getModeManager ();
            if (!cd.hasLayers ())
            {
                ((DeviceParamsMode) modeManager.getMode (Modes.MODE_DEVICE_PARAMS)).setShowDevices (false);
                return;
            }

            final ChannelData layer = cd.getSelectedLayerOrDrumPad ();
            if (layer == null)
                cd.selectLayerOrDrumPad (0);
            modeManager.setActiveMode (Modes.MODE_DEVICE_LAYER);
            return;
        }

        // LONG press - move upwards
        this.surface.setButtonConsumed (PushControlSurface.PUSH_BUTTON_ROW1_1 + index);
        this.moveUp ();
    }