diff --git a/ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptorCacheHelp.java b/ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptorCacheHelp.java
index c4c39ccf44..50aca35044 100644
--- a/ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptorCacheHelp.java
+++ b/ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptorCacheHelp.java
@@ -514,7 +514,7 @@ void beanCachePutAllDirect(Collection<EntityBean> beans) {
 
     if (natKeys != null && !natKeys.isEmpty()) {
       if (natLog.isLoggable(DEBUG)) {
-        natLog.log(DEBUG, " MPUT {0}({1}, {2})", cacheName, naturalKey, natKeys.keySet());
+        natLog.log(DEBUG, " MPUT {0}({1}, {2})", cacheName, Arrays.toString(naturalKey), natKeys.keySet());
       }
       naturalKeyCache.putAll(natKeys);
     }