killbill-memoizeit

diff --git a/jaxrs/src/main/java/org/killbill/billing/jaxrs/json/AccountJson.java b/jaxrs/src/main/java/org/killbill/billing/jaxrs/json/AccountJson.java
index c6916fe..79fd1ec 100644
--- a/jaxrs/src/main/java/org/killbill/billing/jaxrs/json/AccountJson.java
+++ b/jaxrs/src/main/java/org/killbill/billing/jaxrs/json/AccountJson.java
@@ -32,6 +32,7 @@ import org.killbill.billing.util.audit.AccountAuditLogs;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.base.Objects;
+import com.google.common.base.Strings;
 import com.wordnik.swagger.annotations.ApiModelProperty;
 
 public class AccountJson extends JsonBase {
@@ -206,7 +207,7 @@ public class AccountJson extends JsonBase {
 
             @Override
             public Currency getCurrency() {
-                if (currency == null) {
+                if (Strings.emptyToNull(currency) == null) {
                     return null;
                 } else {
                     return Currency.valueOf(currency);