Fix http session wrapping. Check for nulls

code/moya-web/src/main/java/fi/codecrew/moya/web/helper/HttpSessionWrapper.java

@@ -154,10 +154,16 @@ public class HttpSessionWrapper implements HttpSession
 	}
 
 	public static List<HttpSessionWrapper> wrap(Set<HttpSession> sessions, SessionMgmtBeanLocal sessionMgmt) {
-		ArrayList<HttpSessionWrapper> ret = new ArrayList<>();
+		List<HttpSessionWrapper> ret = new ArrayList<>();
 		for (HttpSession s : sessions) {
 			UserContainer uc = sessionMgmt.getUsername(s.getId());
-			ret.add(new HttpSessionWrapper(s, uc.getUsername(), uc.getHostname()));
+			String username = null;
+			String hostname = null;
+			if (uc != null) {
+				username = uc.getUsername();
+				hostname = uc.getHostname();
+			}
+			ret.add(new HttpSessionWrapper(s, username, hostname));
 		}
 		Collections.sort(ret, new LastSeenComparator());