Handle null error message.

1 files changed, 1 insertions, 1 deletions

diff --git a/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java b/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java
index 321f7b3994a..1fcde746878 100644
--- a/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java
+++ b/container-core/src/main/java/com/yahoo/container/handler/metrics/ErrorResponse.java
@@ -18,7 +18,7 @@ public class ErrorResponse extends JsonResponse {
     private static ObjectMapper objectMapper = new ObjectMapper();
 
     public ErrorResponse(int code, String message) {
-        super(code, asErrorJson(message));
+        super(code, asErrorJson(message != null ? message : "<null>"));
     }
 
     static String asErrorJson(String message) {