diff --git a/serving/src/test/java/ai/djl/serving/translator/EchoTranslator.java b/serving/src/test/java/ai/djl/serving/translator/EchoTranslator.java
index fabf62e77..533ec2ff7 100644
--- a/serving/src/test/java/ai/djl/serving/translator/EchoTranslator.java
+++ b/serving/src/test/java/ai/djl/serving/translator/EchoTranslator.java
@@ -37,7 +37,7 @@ public Batchifier getBatchifier() {
     @Override
     public NDList processInput(TranslatorContext ctx, Input input) {
         ctx.setAttachment("input", input);
-        return null;
+        return new NDList();
     }
 
     @Override