killbill-memoizeit

diff --git a/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceItemFormatter.java b/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceItemFormatter.java
index a5bf42e..bb98c74 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceItemFormatter.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceItemFormatter.java
@@ -89,7 +89,7 @@ public class DefaultInvoiceItemFormatter implements InvoiceItemFormatter {
 
     @Override
     public String getFormattedEndDate() {
-        return Strings.nullToEmpty(item.getEndDate().toString(dateFormatter));
+        return Strings.nullToEmpty(item.getEndDate() == null ? null : item.getEndDate().toString(dateFormatter));
     }
 
     @Override