diff --git a/core/src/main/java/org/apache/struts2/dispatcher/StreamResult.java b/core/src/main/java/org/apache/struts2/dispatcher/StreamResult.java
index c8d3facf4..2ab1144f7 100644
--- a/core/src/main/java/org/apache/struts2/dispatcher/StreamResult.java
+++ b/core/src/main/java/org/apache/struts2/dispatcher/StreamResult.java
@@ -260,7 +260,7 @@ public class StreamResult extends StrutsResultSupport {
 
         String contentType = stack.findString("contentType");
         if (contentType != null) {
-            setContentLength(contentType);
+            setContentType(contentType);
         }
 
         String inputName = stack.findString("inputName");