diff --git a/src/main/org/apache/tools/ant/util/NullOutputStream.java b/src/main/org/apache/tools/ant/util/NullOutputStream.java
index 689ac495c..c8e989882 100644
--- a/src/main/org/apache/tools/ant/util/NullOutputStream.java
+++ b/src/main/org/apache/tools/ant/util/NullOutputStream.java
@@ -33,6 +33,8 @@ public class NullOutputStream extends OutputStream {
      */
     public static NullOutputStream INSTANCE = new NullOutputStream();
 
+    private NullOutputStream() { }
+
     /**
      * Doesn't do anything.
      */