--- a/flys-client/ChangeLog	Fri Sep 07 13:15:28 2012 +0000
+++ b/flys-client/ChangeLog	Fri Sep 07 15:58:10 2012 +0000
@@ -1,3 +1,9 @@
+2012-09-07	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
+
+	* src/main/java/de/intevation/flys/client/server/UserServiceImpl.java,
+	  src/main/java/de/intevation/flys/client/server/auth/UserClient.java:
+	  Be more defensive about fetchimg users from session.
+
 2012-09-07	Felix Wolfsteller	<felix.wolfsteller@intevation.de>
 
 	Improved panning in TimeseriesCharts (issue715).

--- a/flys-client/src/main/java/de/intevation/flys/client/server/UserServiceImpl.java	Fri Sep 07 13:15:28 2012 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/server/UserServiceImpl.java	Fri Sep 07 15:58:10 2012 +0000
@@ -1,15 +1,10 @@
 package de.intevation.flys.client.server;
 
-import javax.xml.xpath.XPathConstants;
-
-import org.w3c.dom.Document;
 import org.w3c.dom.Element;
-import org.w3c.dom.NodeList;
 
 import org.apache.log4j.Logger;
 
 import de.intevation.artifacts.common.ArtifactNamespaceContext;
-import de.intevation.artifacts.common.utils.XMLUtils;
 
 import de.intevation.artifacts.httpclient.exceptions.ConnectionException;
 
@@ -39,6 +34,11 @@
         UserClient client = new UserClient(url);
         de.intevation.flys.client.server.auth.User loginuser = getUser();
 
+        if (loginuser == null) {
+            logger.debug("no session user");
+            throw new AuthenticationException(ERROR_NO_SUCH_USER);
+        }
+
         try {
             Element user = client.findUser(loginuser);
 

--- a/flys-client/src/main/java/de/intevation/flys/client/server/auth/UserClient.java	Fri Sep 07 13:15:28 2012 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/server/auth/UserClient.java	Fri Sep 07 15:58:10 2012 +0000
@@ -31,11 +31,12 @@
     }
 
     public boolean userExists(User user) throws ConnectionException {
-        Element data = this.findUser(user);
-
         if (user == null) {
             return false;
         }
+
+        Element data = this.findUser(user);
+
         String XPATH_USERACCOUNT = "/art:user/art:account/@art:name";
 
         String account = XMLUtils.xpathString(
@@ -127,11 +128,19 @@
         action.appendChild(account);
         document.appendChild(action);
 
-        logger.debug("Find user request xml: " + XMLUtils.toString(document));
+        boolean debug = logger.isDebugEnabled();
+
+        if (debug) {
+            logger.debug("Find user request xml: " +
+                XMLUtils.toString(document));
+        }
 
         Document resp = client.findUser(document);
 
-        logger.debug("Find user request response xml: " + XMLUtils.toString(resp));
+        if (debug) {
+            logger.debug("Find user request response xml: " +
+                XMLUtils.toString(resp));
+        }
 
         return resp.getDocumentElement();
     }