Correct equals(Object) method handling if both objects have null getDetails().

core/src/main/java/org/acegisecurity/providers/anonymous/AnonymousAuthenticationToken.java

@@ -78,6 +78,10 @@ public class AnonymousAuthenticationToken extends AbstractAuthenticationToken
                 return false;
             }
 
+            if ((this.details == null) && (test.getDetails() == null)) {
+                return true;
+            }
+
             if ((this.details == null) && (test.getDetails() != null)) {
                 return false;
             }