diff --git a/build.xml b/build.xml
index 400e55028..d895ab916 100644
--- a/build.xml
+++ b/build.xml
@@ -123,7 +123,7 @@
   -->
   <!-- depends on JDK version -->
   <patternset id="needs.jdk1.2+">
-    <exclude name="{util.package}/optional/WeakishReference12.java"
+    <exclude name="${util.package}/optional/WeakishReference12.java"
              unless="jdk1.2+"/>
     <exclude name="${optional.package}/extension/**/*.java"
              unless="jdk1.2+"/>