Attempt to de-reference null object

Question

I am trying to insert queues using metadata api but getting error while inserting sobject in the queue.

MetadataService.QueueSobject obj =new MetadataService.QueueSobject();
obj.sobjectType='Account';      
MetadataService.Queue queue = new MetadataService.Queue();
queue.fullName = 'Account_Queue';
queue.name = 'Account_Queue'; 
System.debug('*****Selected Object*****'+obj.sobjectType); // getting value here.
queue.queueSobject[0].sobjectType = obj.sobjectType;  // Getting attempt to de-refrence null object

MetadataService.MetadataPort service = createService(); 
List<MetadataService.SaveResult> results = service.createMetadata(new 
MetadataService.Metadata[] { queue });
handleSaveResults(results[0]);

queue.queueSobject[0].sobjectType = obj.sobjectType; -- This line throwing error.

obj.sobjectType is not getting stored in queue.queueSobject[0].sobjectType. How can I fix it ?

Answer 1

NPE in your code is most likely related to the fact that you are trying to reference queue.queueSobject collection which you have not initialised yet.

Try changing line

queue.queueSobject[0].sobjectType = obj.sobjectType; 

to something like this:

queue.queueSobject = new List<QueueSobject>();
final QueueSobject qsobj = new QueueSobject();
qsobj.sobjectType = 'Account'
queue.queueSobject.add(qsobj);