killbill-memoizeit

diff --git a/invoice/src/main/java/org/killbill/billing/invoice/tree/AccountItemTree.java b/invoice/src/main/java/org/killbill/billing/invoice/tree/AccountItemTree.java
index 75369f8..0e01b33 100644
--- a/invoice/src/main/java/org/killbill/billing/invoice/tree/AccountItemTree.java
+++ b/invoice/src/main/java/org/killbill/billing/invoice/tree/AccountItemTree.java
@@ -1,7 +1,9 @@
 /*
  * Copyright 2010-2014 Ning, Inc.
+ * Copyright 2014-2015 Groupon, Inc
+ * Copyright 2014-2015 The Billing Project, LLC
  *
- * Ning licenses this file to you under the Apache License, version 2.0
+ * The Billing Project licenses this file to you under the Apache License, version 2.0
  * (the "License"); you may not use this file except in compliance with the
  * License.  You may obtain a copy of the License at:
  *
@@ -117,7 +119,7 @@ public class AccountItemTree {
         allExistingItems.add(existingItem);
 
         final UUID subscriptionId = getSubscriptionId(existingItem, allExistingItems);
-        Preconditions.checkState(subscriptionId != null || !failOnMissingSubscription);
+        Preconditions.checkState(subscriptionId != null || !failOnMissingSubscription, "Missing subscription id");
 
         if (subscriptionId == null && existingItem.getInvoiceItemType() == InvoiceItemType.ITEM_ADJ) {
             pendingItemAdj.add(existingItem);

diff --git a/invoice/src/main/java/org/killbill/billing/invoice/tree/ItemsNodeInterval.java b/invoice/src/main/java/org/killbill/billing/invoice/tree/ItemsNodeInterval.java
index a2c5d51..48e946a 100644
--- a/invoice/src/main/java/org/killbill/billing/invoice/tree/ItemsNodeInterval.java
+++ b/invoice/src/main/java/org/killbill/billing/invoice/tree/ItemsNodeInterval.java
@@ -1,7 +1,9 @@
 /*
  * Copyright 2010-2014 Ning, Inc.
+ * Copyright 2014-2015 Groupon, Inc
+ * Copyright 2014-2015 The Billing Project, LLC
  *
- * Ning licenses this file to you under the Apache License, version 2.0
+ * The Billing Project licenses this file to you under the Apache License, version 2.0
  * (the "License"); you may not use this file except in compliance with the
  * License.  You may obtain a copy of the License at:
  *
@@ -232,7 +234,7 @@ public class ItemsNodeInterval extends NodeInterval {
                 return ((ItemsNodeInterval) curNode).getItemsInterval().containsItem(targetId);
             }
         });
-        Preconditions.checkNotNull(node, "Cannot add adjustement for item = " + targetId + ", date = " + adjustementDate);
+        Preconditions.checkNotNull(node, "Cannot add adjustment for item = " + targetId + ", date = " + adjustementDate);
         ((ItemsNodeInterval) node).setAdjustment(amount.negate(), targetId);
     }