diff --git a/src/main/java/org/apache/commons/fileupload/MultipartStream.java b/src/main/java/org/apache/commons/fileupload/MultipartStream.java
index 70985bd..2c58e7e 100644
--- a/src/main/java/org/apache/commons/fileupload/MultipartStream.java
+++ b/src/main/java/org/apache/commons/fileupload/MultipartStream.java
@@ -230,7 +230,7 @@
     /**
      * The table for Knuth-Morris-Pratt search algorithm.
      */
-    private int[] boundaryTable;
+    private final int[] boundaryTable;
 
     /**
      * The length of the buffer used for processing the request.
diff --git a/src/test/java/org/apache/commons/fileupload/MockHttpServletRequest.java b/src/test/java/org/apache/commons/fileupload/MockHttpServletRequest.java
index 0d9673d..07ca064 100644
--- a/src/test/java/org/apache/commons/fileupload/MockHttpServletRequest.java
+++ b/src/test/java/org/apache/commons/fileupload/MockHttpServletRequest.java
@@ -38,7 +38,7 @@
 
     private long length;
 
-    private String m_strContentType;
+    private final String m_strContentType;
 
     private int readLimit = -1;
 
diff --git a/src/test/java/org/apache/commons/fileupload/portlet/MockPortletActionRequest.java b/src/test/java/org/apache/commons/fileupload/portlet/MockPortletActionRequest.java
index 5f13788..b9a3a1b 100644
--- a/src/test/java/org/apache/commons/fileupload/portlet/MockPortletActionRequest.java
+++ b/src/test/java/org/apache/commons/fileupload/portlet/MockPortletActionRequest.java
@@ -53,7 +53,7 @@
     private final Map<String, String> parameters = new HashMap<String, String>();
 
     private String characterEncoding;
-    private int length;
+    private final int length;
     private final String contentType;
     private final InputStream requestData;