diff --git a/core/src/main/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptor.java b/core/src/main/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptor.java
index 60dea3612..37dbd9a21 100644
--- a/core/src/main/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptor.java
+++ b/core/src/main/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptor.java
@@ -98,6 +98,7 @@ public class JSONValidationInterceptor extends MethodFilterInterceptor {
                     if (validationFailedStatus >= 0)
                         response.setStatus(validationFailedStatus);
                     response.getWriter().print(buildResponse(validationAware));
+                    response.setContentType("application/json");
                     return Action.NONE;
                 }
             }
@@ -106,6 +107,7 @@ public class JSONValidationInterceptor extends MethodFilterInterceptor {
             if (validateOnly != null && "true".equals(validateOnly)) {
                 //there were no errors
                 response.getWriter().print("/* {} */");
+                response.setContentType("application/json");
                 return Action.NONE;
             } else {
                 return invocation.invoke();
diff --git a/core/src/test/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptorTest.java b/core/src/test/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptorTest.java
index 7ad19f06d..e42cb4880 100644
--- a/core/src/test/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptorTest.java
+++ b/core/src/test/java/org/apache/struts2/interceptor/validation/JSONValidationInterceptorTest.java
@@ -78,6 +78,8 @@ public class JSONValidationInterceptorTest extends StrutsTestCase {
         assertFalse(action.isExecuted());
         //http status
         assertEquals(HttpServletResponse.SC_BAD_REQUEST, response.getStatus());
+        assertEquals("application/json", response.getContentType());
+
     }
 
     public void testValidationSucceeds() throws Exception {
@@ -119,6 +121,7 @@ public class JSONValidationInterceptorTest extends StrutsTestCase {
         String normalizedActual = TestUtils.normalize(json, true);
         assertEquals("/*{}*/", normalizedActual);
         assertFalse(action.isExecuted());
+        assertEquals("application/json", response.getContentType());
     }
 
     protected void setUp() throws Exception {
diff --git a/core/src/test/java/org/apache/struts2/views/jsp/StrutsMockHttpServletResponse.java b/core/src/test/java/org/apache/struts2/views/jsp/StrutsMockHttpServletResponse.java
index 8cde39dd4..b38f4c06f 100644
--- a/core/src/test/java/org/apache/struts2/views/jsp/StrutsMockHttpServletResponse.java
+++ b/core/src/test/java/org/apache/struts2/views/jsp/StrutsMockHttpServletResponse.java
@@ -37,6 +37,7 @@ public class StrutsMockHttpServletResponse extends MockHttpServletResponse {
     private PrintWriter writer;
     private int status;
     private String redirectURL;
+    private String contentType;
 
     public Locale getLocale() {
         return locale;
@@ -47,7 +48,12 @@ public class StrutsMockHttpServletResponse extends MockHttpServletResponse {
     }
 
     public String getContentType() {
-        return null;  //To change body of implemented methods use File | Settings | File Templates.
+        return contentType;  //To change body of implemented methods use File | Settings | File Templates.
+    }
+    
+    @Override
+    public void setContentType(String type) {
+        this.contentType = type;
     }
 
     public PrintWriter getWriter() throws IOException {