Catch NFE in WSHandler
diff --git a/ws-security-dom/src/main/java/org/apache/wss4j/dom/handler/WSHandler.java b/ws-security-dom/src/main/java/org/apache/wss4j/dom/handler/WSHandler.java
index 39bbbca..cddc996 100644
--- a/ws-security-dom/src/main/java/org/apache/wss4j/dom/handler/WSHandler.java
+++ b/ws-security-dom/src/main/java/org/apache/wss4j/dom/handler/WSHandler.java
@@ -529,8 +529,12 @@
 
         String iterations = getString(WSHandlerConstants.DERIVED_KEY_ITERATIONS, mc);
         if (iterations != null) {
-            int iIterations = Integer.parseInt(iterations);
-            reqData.setDerivedKeyIterations(iIterations);
+            try {
+                int iIterations = Integer.parseInt(iterations);
+                reqData.setDerivedKeyIterations(iIterations);
+            } catch (NumberFormatException e) {
+                LOG.warn("Error in configuring a derived key iteration count: " + e.getMessage());
+            }
         }
     }