diff --git a/src/checkstyle/com/puppycrawl/tools/checkstyle/Defn.java b/src/checkstyle/com/puppycrawl/tools/checkstyle/Defn.java
index cbf7adda4..20350a9ec 100644
--- a/src/checkstyle/com/puppycrawl/tools/checkstyle/Defn.java
+++ b/src/checkstyle/com/puppycrawl/tools/checkstyle/Defn.java
@@ -24,6 +24,13 @@ package com.puppycrawl.tools.checkstyle;
  **/
 public final class Defn
 {
+    /**
+     * Do no allow <code>Defn</code> instances to be created.
+     **/
+    private Defn() 
+    {
+    }
+
     /** name of resource bundle for Checkstyle */
     public static final String CHECKSTYLE_BUNDLE =
             "com.puppycrawl.tools.checkstyle.messages";