killbill-aplcache

diff --git a/invoice/src/main/java/org/killbill/billing/invoice/usage/details/UsageConsumableInArrearDetail.java b/invoice/src/main/java/org/killbill/billing/invoice/usage/details/UsageConsumableInArrearDetail.java
index 8d690bb..3ae70b0 100644
--- a/invoice/src/main/java/org/killbill/billing/invoice/usage/details/UsageConsumableInArrearDetail.java
+++ b/invoice/src/main/java/org/killbill/billing/invoice/usage/details/UsageConsumableInArrearDetail.java
@@ -26,9 +26,9 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 public class UsageConsumableInArrearDetail implements UsageInArrearDetail {
 
     private final List<UsageConsumableInArrearTierUnitDetail> tierDetails;
-    private BigDecimal amount;
+    private final BigDecimal amount;
 
-    public UsageConsumableInArrearDetail(@JsonProperty("tierDetails") List<UsageConsumableInArrearTierUnitDetail> tierDetails) {
+    public UsageConsumableInArrearDetail(List<UsageConsumableInArrearTierUnitDetail> tierDetails) {
         this(tierDetails, computeAmount(tierDetails));
     }