use OAIPMHUtilites.fieldLoader instead of DublinCore.fillList. Set DublinCore.fill to depreacted

oaipmh-core/src/main/java/info/textgrid/middleware/DublinCoreFieldLoader.java

@@ -113,7 +113,7 @@ public class DublinCoreFieldLoader {
     return dates;
   }
 
-
+  @Deprecated
   public static List<String> fillList(GetResponse responseWorkValues, String[] fields) {
     
     List<String> list = new ArrayList<String>();

oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDC.java

@@ -281,7 +281,8 @@ public class RecordDelivererDC extends RecordDelivererAbstract {
         DublinCoreFieldLoader.fillList(responseWorkValues, this.descriptionList));
     result.setFormat(DublinCoreFieldLoader.fillList(responseWorkValues, this.formatList));
     result.setIdentifier(
-        DublinCoreFieldLoader.fillList(responseWorkValues, this.identifierList));
+    	OAIPMHUtilities.fieldLoader(new JSONObject(responseWorkValues.getSourceAsMap()), this.identifierList));
+    
     result.setLanguage(DublinCoreFieldLoader.fillList(responseWorkValues, this.languageList));
     result.setPublisher(DublinCoreFieldLoader.fillList(responseWorkValues, this.publisherList));
     result.setRelation(