Query Worklist error

[Samuel Thomas]

Error: I am trying to query a modality worklist but experiencing error indicating no presentation context.

Question: How can I specify the " Modality Worklist SOP Class" in the below method.

"1.2.840.10008.5.1.4.31",  /// Modality Worklist SOP Class

---------------------------------------------------------------------------------------------------------------------------------

SpecificCharacterSet specificCharacterSet = new SpecificCharacterSet((String[])null);
            AttributeList identifier = new AttributeList();

            identifier.putNewAttribute(TagFromName.QueryRetrieveLevel).addValue("STUDY");
            identifier.putNewAttribute(TagFromName.PatientName,specificCharacterSet);
            identifier.putNewAttribute(TagFromName.PatientID,specificCharacterSet);
            identifier.putNewAttribute(TagFromName.PatientBirthDate);
            identifier.putNewAttribute(TagFromName.PatientSex);
            identifier.putNewAttribute(TagFromName.StudyInstanceUID);
            identifier.putNewAttribute(TagFromName.SOPInstanceUID);
            identifier.putNewAttribute(TagFromName.StudyDescription);
            identifier.putNewAttribute(TagFromName.StudyDate);
            identifier.putNewAttribute(TagFromName.AccessionNumber);
           
            new FindSOPClassSCU("www.local.co.uk",104,"AET","AEC", //Specify the correct URL and parameters
                    SOPClass.StudyRootQueryRetrieveInformationModelFind,identifier,
                    new OurCustomFindIdentifierHandler());