Added more condition to check authorship

src/main/java/org/gcube/gcat/persistence/ckan/CKANPackage.java

@@ -279,11 +279,11 @@ public class CKANPackage extends CKAN implements Moderated {
 		}else { // this prevent to change the original author in case of update
 			Role role = ckanUser.getRole();
 			if(role.ordinal() <  Role.ADMIN.ordinal()) {
-				if(objectNode.get(AUTHOR_KEY).asText().compareTo(authorName)!=0) {
+				if(objectNode.has(AUTHOR_KEY) && objectNode.get(AUTHOR_KEY).asText().compareTo(authorName)!=0) {
 					throw new BadRequestException("Only Catalogue-Admins or above can change the authorship (i.e. " + AUTHOR_KEY + " field) of an item.");
 				}
 				
-				if(objectNode.get(AUTHOR_EMAIL_KEY).asText().compareTo(authorEmail)!=0) {
+				if(objectNode.has(AUTHOR_EMAIL_KEY) && objectNode.get(AUTHOR_EMAIL_KEY).asText().compareTo(authorEmail)!=0) {
 					throw new BadRequestException("Only Catalogue-Admins or above can change the authorship (i.e. " + AUTHOR_EMAIL_KEY + " field) of an item.");
 				}
 			}else {