diff --git a/moco-core/src/main/java/com/github/dreamhead/moco/model/DefaultHttpMessage.java b/moco-core/src/main/java/com/github/dreamhead/moco/model/DefaultHttpMessage.java
index d33cd0774..3f47a5f71 100644
--- a/moco-core/src/main/java/com/github/dreamhead/moco/model/DefaultHttpMessage.java
+++ b/moco-core/src/main/java/com/github/dreamhead/moco/model/DefaultHttpMessage.java
@@ -99,7 +99,7 @@ protected abstract static class Builder<T extends Builder> {
         private Map<String, String[]> headers;
 
         @SuppressWarnings("unchecked")
-        public Builder() {
+        protected Builder() {
             this.clazz = (Class<T>) TypeToken.of(getClass()).getRawType();
         }