diff --git a/generator/src/main/java/org/apache/kafka/message/MessageDataGenerator.java b/generator/src/main/java/org/apache/kafka/message/MessageDataGenerator.java
index 14ab1d01f7258..b3c243e73d4fb 100644
--- a/generator/src/main/java/org/apache/kafka/message/MessageDataGenerator.java
+++ b/generator/src/main/java/org/apache/kafka/message/MessageDataGenerator.java
@@ -1578,7 +1578,7 @@ private void generateFieldMutator(String className, FieldSpec field) {
             buffer.printf("if (v < 0 || v > 65535) {%n");
             buffer.incrementIndent();
             buffer.printf("throw new RuntimeException(\"Invalid value \" + v + " +
-                    "\"for unsigned short field.\");%n");
+                    "\" for unsigned short field.\");%n");
             buffer.decrementIndent();
             buffer.printf("}%n");
         }