QPID-1469: Fix NullPointerException, add test for deleteUser which would expose this.

Patch from gemmellr@dcs.gla.ac.uk

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@724787 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 5 insertions, 0 deletions

diff --git a/java/broker/src/main/java/org/apache/qpid/server/security/access/management/AMQUserManagementMBean.java b/java/broker/src/main/java/org/apache/qpid/server/security/access/management/AMQUserManagementMBean.java
index a8ae03cc5d..32ec3a3bbc 100644
--- a/java/broker/src/main/java/org/apache/qpid/server/security/access/management/AMQUserManagementMBean.java
+++ b/java/broker/src/main/java/org/apache/qpid/server/security/access/management/AMQUserManagementMBean.java
@@ -441,7 +441,12 @@ public class AMQUserManagementMBean extends AMQManagedObject implements UserMana
     private String getCurrentJMXUser()
     {
         AccessControlContext acc = AccessController.getContext();
+        
         Subject subject = Subject.getSubject(acc);
+        if (subject == null)
+        {
+            return "Unknown user, authentication Subject was null";
+        }
 
         // Retrieve JMXPrincipal from Subject
         Set<JMXPrincipal> principals = subject.getPrincipals(JMXPrincipal.class);