diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/server/utils/MetadataDiscovery.java b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/server/utils/MetadataDiscovery.java
index ce69f30..a163f40 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/server/utils/MetadataDiscovery.java
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/server/utils/MetadataDiscovery.java
@@ -177,74 +177,75 @@ public class MetadataDiscovery {
 					Map<String, List<MetadataFieldWrapper>> fieldsPerCategory = new HashMap<String, List<MetadataFieldWrapper>>(categoriesWrapper.size());
 
 					// manage the fields
-					for(MetadataField metadataField: fields){
+					if(fields != null)
+						for(MetadataField metadataField: fields){
 
-						MetadataFieldWrapper wrapperObj = new MetadataFieldWrapper();
-						wrapperObj.setFieldNameFromCategory(metadataField.getCategoryFieldQName());
-						wrapperObj.setType(DataTypeWrapper.valueOf(metadataField.getDataType().toString()));
-						wrapperObj.setDefaultValue(metadataField.getDefaultValue());
-						wrapperObj.setFieldName(metadataField.getFieldName());
-						wrapperObj.setMandatory(metadataField.getMandatory());
-						wrapperObj.setNote(metadataField.getNote());
-						MetadataValidator validator = metadataField.getValidator();
-						if(validator != null)
-							wrapperObj.setValidator(validator.getRegularExpression());
+							MetadataFieldWrapper wrapperObj = new MetadataFieldWrapper();
+							wrapperObj.setFieldNameFromCategory(metadataField.getCategoryFieldQName());
+							wrapperObj.setType(DataTypeWrapper.valueOf(metadataField.getDataType().toString()));
+							wrapperObj.setDefaultValue(metadataField.getDefaultValue());
+							wrapperObj.setFieldName(metadataField.getFieldName());
+							wrapperObj.setMandatory(metadataField.getMandatory());
+							wrapperObj.setNote(metadataField.getNote());
+							MetadataValidator validator = metadataField.getValidator();
+							if(validator != null)
+								wrapperObj.setValidator(validator.getRegularExpression());
 
-						MetadataVocabulary vocabulary = metadataField.getVocabulary();
+							MetadataVocabulary vocabulary = metadataField.getVocabulary();
 
-						if(vocabulary != null){
-							wrapperObj.setVocabulary(vocabulary.getVocabularyFields());	
-							wrapperObj.setMultiSelection(vocabulary.isMultiSelection());
-						}
-
-						MetadataTagging tagging = metadataField.getTagging();
-						if(tagging != null){
-
-							FieldAsTag tag = new FieldAsTag();
-							tag.setCreate(tagging.getCreate());
-							tag.setSeparator(tagging.getSeparator());
-							tag.setTaggingValue(TaggingGroupingValue.valueOf(tagging.getTaggingValue().toString()));
-							wrapperObj.setAsTag(tag);
-
-						}
-
-						MetadataGrouping grouping = metadataField.getGrouping();
-						if(grouping != null){
-
-							FieldAsGroup group = new FieldAsGroup();
-							group.setCreate(grouping.getCreate());
-							group.setPropagateUp(grouping.getPropagateUp());
-							group.setGroupingValue(TaggingGroupingValue.valueOf(grouping.getGroupingValue().toString()));
-							wrapperObj.setAsGroup(group);
-
-						}
-
-						// set to which category this field belongs to and vice-versa
-						if(metadataField.getCategoryRef() != null){
-							CategoryWrapper ownerCategory = idToCategory.get(metadataField.getCategoryRef());
-
-							if(ownerCategory == null){
-								logger.warn("A field with categoryref "  + metadataField.getCategoryRef() + " has been found, but"
-										+ " such category is not defined within the namespaces");
-							}else{
-
-								wrapperObj.setOwnerCategory(ownerCategory);
-
-								List<MetadataFieldWrapper> fieldsPerCategoryN = fieldsPerCategory.get(metadataField.getCategoryRef()); 
-								if(fieldsPerCategoryN == null)
-									fieldsPerCategoryN = new ArrayList<MetadataFieldWrapper>();
-
-								fieldsPerCategoryN.add(wrapperObj);
-								fieldsPerCategory.put(metadataField.getCategoryRef(), fieldsPerCategoryN);
-
-								// instead of re-looping on the fieldsPerCategory map later, just set this potentially partial list
-								ownerCategory.setFieldsForThisCategory(fieldsPerCategoryN);
+							if(vocabulary != null){
+								wrapperObj.setVocabulary(vocabulary.getVocabularyFields());	
+								wrapperObj.setMultiSelection(vocabulary.isMultiSelection());
 							}
+
+							MetadataTagging tagging = metadataField.getTagging();
+							if(tagging != null){
+
+								FieldAsTag tag = new FieldAsTag();
+								tag.setCreate(tagging.getCreate());
+								tag.setSeparator(tagging.getSeparator());
+								tag.setTaggingValue(TaggingGroupingValue.valueOf(tagging.getTaggingValue().toString()));
+								wrapperObj.setAsTag(tag);
+
+							}
+
+							MetadataGrouping grouping = metadataField.getGrouping();
+							if(grouping != null){
+
+								FieldAsGroup group = new FieldAsGroup();
+								group.setCreate(grouping.getCreate());
+								group.setPropagateUp(grouping.getPropagateUp());
+								group.setGroupingValue(TaggingGroupingValue.valueOf(grouping.getGroupingValue().toString()));
+								wrapperObj.setAsGroup(group);
+
+							}
+
+							// set to which category this field belongs to and vice-versa
+							if(metadataField.getCategoryRef() != null){
+								CategoryWrapper ownerCategory = idToCategory.get(metadataField.getCategoryRef());
+
+								if(ownerCategory == null){
+									logger.warn("A field with categoryref "  + metadataField.getCategoryRef() + " has been found, but"
+											+ " such category is not defined within the namespaces");
+								}else{
+
+									wrapperObj.setOwnerCategory(ownerCategory);
+
+									List<MetadataFieldWrapper> fieldsPerCategoryN = fieldsPerCategory.get(metadataField.getCategoryRef()); 
+									if(fieldsPerCategoryN == null)
+										fieldsPerCategoryN = new ArrayList<MetadataFieldWrapper>();
+
+									fieldsPerCategoryN.add(wrapperObj);
+									fieldsPerCategory.put(metadataField.getCategoryRef(), fieldsPerCategoryN);
+
+									// instead of re-looping on the fieldsPerCategory map later, just set this potentially partial list
+									ownerCategory.setFieldsForThisCategory(fieldsPerCategoryN);
+								}
+							}
+
+							fieldsWrapper.add(wrapperObj);
 						}
 
-						fieldsWrapper.add(wrapperObj);
-					}
-					
 					// filter the categories without children here
 					Iterator<CategoryWrapper> categoryToRemoveIT = categoriesWrapper.iterator();
 					while (categoryToRemoveIT.hasNext()) {
@@ -253,7 +254,7 @@ public class MetadataDiscovery {
 						if(categoryWrapper.getFieldsForThisCategory() == null)
 							categoryToRemoveIT.remove();
 					}
-					
+
 					MetaDataProfileBean bean = new MetaDataProfileBean(type, title, fieldsWrapper, categoriesWrapper);
 					beans.add(bean);
 				}