Merge pull request sakaiproject#47 from baholladay/SAK-28988

SAK-28988 Delegated Access: Concurrent hashmaps throw NPE when storing null values

delegatedaccess/impl/src/java/org/sakaiproject/delegatedaccess/logic/ProjectLogicImpl.java

@@ -1806,9 +1806,9 @@ private Map<String, AccessNode> grantAccessToSites(List<String> siteRefs, boolea
 			}else{
 				//set default to no access and override it if the user does have access
 				//this is so we don't have to keep looking up their access for the same site:
-				deniedAuthToolsMap.put(siteRef, null);
-				deniedPublicToolsMap.put(siteRef, null);
-				accessMap.put(siteRef, null);
+				deniedAuthToolsMap.put(siteRef, new String[0]);
+				deniedPublicToolsMap.put(siteRef, new String[0]);
+				accessMap.put(siteRef, new String[0]);
 			}
 		}
 		//Set user Id and hierarchy id