NullPointerException decoding PlannerChecklistItem

[klehmann]

We are trying to read MS Planner plans details and check list items via graph API and get a NullPointerException.

Expected behavior

PlannerChecklistItem can be decoded properly.

Actual behavior

Code throws NullPointerException.

Steps to reproduce the behavior

Create an MS Planner plan and add a task with a checklist item.

Use getGroups to read all groups:

	public static List<Group> getGroups(IGraphServiceClient graphAPI) {
		List<Group> allGroups = new ArrayList<>();
		
		IGroupCollectionRequest groupsReq = graphAPI.groups().buildRequest();
		IGroupCollectionPage currGroupPage;
		do {
			currGroupPage = groupsReq.get();
			
			List<Group> groupsInPage = currGroupPage.getCurrentPage();
			allGroups.addAll(groupsInPage);
			
			IGroupCollectionRequestBuilder nextPageReq = currGroupPage.getNextPage();
			if (nextPageReq==null) {
				break;
			}
			else {
				groupsReq = nextPageReq.buildRequest();
			}
		}
		while (true);
		
		return allGroups;
	}

Find the group corresponding to the plan and use getPlansForGroup to read the plan:

	public static List<PlannerPlan> getPlansForGroup(IGraphServiceClient graphAPI, Group group) {
		List<PlannerPlan> allPlans = new ArrayList<>();
		
		IPlannerPlanCollectionRequest plansReq = graphAPI.groups(group.id).planner().plans().buildRequest();
		IPlannerPlanCollectionPage currPlanPage;
		do {
			currPlanPage = plansReq.get();
			List<PlannerPlan> plansForPage = currPlanPage.getCurrentPage();
			
			for (PlannerPlan currPlan : plansForPage) {
				allPlans.add(currPlan);
			}
		
			IPlannerPlanCollectionRequestBuilder nextPageReq = currPlanPage.getNextPage();
			if (nextPageReq==null) {
				break;
			}
			else {
				plansReq = nextPageReq.buildRequest();
			}
		}
		while (true);
		
		return allPlans;
	}

For the returned plan, call getTasksForPlan to get all the tasks:

	public static List<PlannerTask> getTasksForPlan(IGraphServiceClient graphAPI, PlannerPlan plan) {
		List<PlannerTask> allTasks = new ArrayList<>();
		
		IPlannerTaskCollectionPage tasksPage = graphAPI.planner().plans(plan.id).tasks().buildRequest().get();
		do {
			List<PlannerTask> tasksInPage = tasksPage.getCurrentPage();
			allTasks.addAll(tasksInPage);
			
			IPlannerTaskCollectionRequestBuilder taskReqBuilder = tasksPage.getNextPage();
			if (taskReqBuilder==null) {
				break;
			}
			else {
				tasksPage = taskReqBuilder.buildRequest().get();
			}
		}
		while (true);
		
		return allTasks;
	}

Now try to read the task details:

	public static PlannerTaskDetails getTaskDetails(IGraphServiceClient graphAPI, PlannerTask task) {
		PlannerTaskDetails details = graphAPI.planner().tasks(task.id).details().buildRequest().get();
		return details;
	}

This returns JSON data looks like this:

{
	"references": {},
	"@odata.etag": "W/\"JzEtVGFza0RldGFpbHMgQEBAQEBAQEBAQEBAQEBAUCc=\"",
	"description": null,
	"checklist": {
		"42660": {
			"lastModifiedDateTime": "2018-10-28T14:29:37.7423391Z",
			"@odata.type": "#microsoft.graph.plannerChecklistItem",
			"orderHint": "8586608699726429822PK",
			"lastModifiedBy": {
				"user": {
					"displayName": null,
					"id": "f3a1dfe8-f2ef-4870-9642-413d468c571c"
				}
			},
			"title": "Ein Checklisteneintrag",
			"isChecked": false
		}
	},
	"@odata.context": "https://graph.microsoft.com/v1.0/$metadata#planner/tasks('C6iIn6oJcEGcLX5XAiKeCZcAOv30')/details/$entity",
	"previewType": "automatic",
	"id": "C6iIn6oJcEGcLX5XAiKeCZcAOv30"
}

Deserialization to PlannerTaskDetails fails, because the JSON structure does not match the fields in PlannerChecklistItems.

Caused by: java.lang.NullPointerException
	at com.microsoft.graph.serializer.DefaultSerializer.setChildAdditionalData(DefaultSerializer.java:147)
	at com.microsoft.graph.serializer.DefaultSerializer.setChildAdditionalData(DefaultSerializer.java:138)
	at com.microsoft.graph.serializer.DefaultSerializer.deserializeObject(DefaultSerializer.java:103)

The reason is that the deserializer tried to read a value for public com.microsoft.graph.models.extensions.IdentitySet com.microsoft.graph.models.generated.BasePlannerChecklistItem.lastModifiedBy in this rawJson value (where only key "42660" exists):

{"42660":{"lastModifiedDateTime":"2018-10-28T14:29:37.7423391Z","@odata.type":"#microsoft.graph.plannerChecklistItem","orderHint":"8586608699726429822PK","lastModifiedBy":{"user":{"displayName":"","id":"f3a1dfe8-f2ef-4870-9642-413d468c571c"}},"title":"Ein Checklisteneintrag","isChecked":false}}

[klehmann]

Worked around the issue by using a custom serializer where I added null checks for rawJson.get(field.getName()) and outJson.get(field.getName()) like this:

      // If the object is a valid Graph object, set its additional data
      else if (fieldObject != null && fieldObject instanceof IJsonBackedObject) {
          IJsonBackedObject serializedChild = (IJsonBackedObject) fieldObject;

          JsonElement rawJsonEl = rawJson.get(field.getName());
          if (rawJsonEl!=null) {
              setAdditionalData(serializedChild, rawJsonEl.getAsJsonObject());
              setChildAdditionalData((IJsonBackedObject) fieldObject,rawJsonEl.getAsJsonObject());
          }
      }

	// If the object is a valid Graph object, add its additional data
	else if (fieldObject != null && fieldObject instanceof IJsonBackedObject) {
		IJsonBackedObject serializableChild = (IJsonBackedObject) fieldObject;
		AdditionalDataManager childAdditionalData = serializableChild.additionalDataManager();

		JsonElement outJsonEl = outJson.get(field.getName());
		if (outJsonEl!=null) {
			addAdditionalDataToJson(childAdditionalData, outJsonEl.getAsJsonObject());
		}
            		
       		// Serialize its children
       		outJson = getChildAdditionalData(serializableChild, outJson);
	} 

[deepak2016]

Thank you for reporting your issue. We are looking into it.

[J0s3f]

We have exactly the same NullPointerException when fetching ListItem from Drive

fileMetadata = graphClient.drives(driveId).items(item.id).listItem().buildRequest().get();

[hg64]

Is there an update on this? We also have this problem:

DriveItem driveItem = graphServiceClient
.groups(groupId)
.drive()
.root()
.itemWithPath(id + ".docx")
.content()
.buildRequest()
.put(t_out.toByteArray());

[hg64]

getting the same error on most methods it seems.....

Caused by: java.lang.NullPointerException
at com.microsoft.graph.serializer.DefaultSerializer.setChildAdditionalData(DefaultSerializer.java:147)

when executing

graphServiceClient
.groups(groupId)
.drive()
.root()
.itemWithPath(p_filename)
.createLink("edit", "organization")
.buildRequest()
.post()
.link
.webUrl;

[NakulSabharwal]

Hi, @klehmann we have repro your issue. We are adding null checks to resolve this issue.
@hg64 the code snippet provided above is working fine because of which we were not able to repro your issue.

[NakulSabharwal]

@hg64 Could you please give full error stack trace and also tell what is the visibility of group you are trying to access using
graphClient.groups(group.id).buildRequest().get().getRawObject(); or graphClient.groups(group.id).buildRequest().get().visibility;

[NakulSabharwal]

@hg64 This seems to be problem of permissions( https://docs.microsoft.com/en-us/graph/api/group-get?view=graph-rest-1.0 ). Could you follow these steps for troubleshooting-

1. goto https://developer.microsoft.com/en-us/graph/graph-explorer#
2. Login with the account you are using to make api call
3. make a GET call to https://graph.microsoft.com/v1.0/groups/520559ee-2d6e-4b01-810d-b3f93afbaf67 and tells whats the result
4. goto modify permissions( top-left) and check if you have Group.ReadWrite.All permission granted or not.
   If your application doesn't have required permission please follow https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-permissions-and-consent#request-the-permissions-in-the-app-registration-portal

[NakulSabharwal]

@hg64 Hi, if you are getting errors even after assigning required permission to your application using Application registration portal then please make a new issue and we will look into it. Thanks.