Need Help with Potential null pointer access

milo · August 7, 2023, 11:34am

Hello,

I get this warning

VolumioHandler.java:[97,25] Potential null pointer access: this expression has a '@Nullable' type

in this line

github.com

openhab/openhab-addons/blob/3b9b0236b46436ce0d91bf95b153eb300f2f3f47/bundles/org.openhab.binding.volumio/src/main/java/org/openhab/binding/volumio/internal/VolumioHandler.java#L97


      
          
          case VolumioBindingConstants.CHANNEL_ARTIST:
          case VolumioBindingConstants.CHANNEL_ALBUM:
          case VolumioBindingConstants.CHANNEL_TRACK_TYPE:
          case VolumioBindingConstants.CHANNEL_TITLE:
              break;
          
          case VolumioBindingConstants.CHANNEL_PLAY_RADIO_STREAM:
              if (command instanceof StringType) {
                  final String uri = command.toFullString();
                  volumio.replacePlay(uri, "Radio", VolumioServiceTypes.WEBRADIO);
              }
          
              break;
          
          case VolumioBindingConstants.CHANNEL_PLAY_URI:
              if (command instanceof StringType) {
                  final String uri = command.toFullString();
                  volumio.replacePlay(uri, "URI", VolumioServiceTypes.WEBRADIO);
              }

How can i solve it?

wborn · August 7, 2023, 11:39am

Assign volumio to a new local variable before doing the null check. Use the local variable everywhere in the method instead of the field.

Rationale: The field can be assigned null by another thread at any moment so it is not safe to use.