diff --git a/httpmime/src/main/java/org/apache/http/entity/mime/FormBodyPart.java b/httpmime/src/main/java/org/apache/http/entity/mime/FormBodyPart.java
index 6115c4549..fbf120291 100644
--- a/httpmime/src/main/java/org/apache/http/entity/mime/FormBodyPart.java
+++ b/httpmime/src/main/java/org/apache/http/entity/mime/FormBodyPart.java
@@ -41,7 +41,7 @@ public class FormBodyPart {
     private final String name;
     private final Header header;
 
-    private ContentBody body;
+    private final ContentBody body;
 
     public FormBodyPart(final String name, final ContentBody body) {
         super();