diff --git a/build.xml b/build.xml
index 3e00952d7..6e1729420 100644
--- a/build.xml
+++ b/build.xml
@@ -123,6 +123,8 @@
   -->
   <!-- depends on JDK version -->
   <patternset id="needs.jdk1.2+">
+    <exclude name="${ant.package}/util/WeakishReference12.java"
+             unless="jdk1.2+"/>
     <exclude name="${optional.package}/extension/**/*.java"
              unless="jdk1.2+"/>
     <exclude name="${util.package}/optional/NoExitSecurityManager.java"
diff --git a/src/main/org/apache/tools/ant/taskdefs/optional/dotnet/DotnetCompile.java b/src/main/org/apache/tools/ant/taskdefs/optional/dotnet/DotnetCompile.java
index ee5d55d19..73d040444 100644
--- a/src/main/org/apache/tools/ant/taskdefs/optional/dotnet/DotnetCompile.java
+++ b/src/main/org/apache/tools/ant/taskdefs/optional/dotnet/DotnetCompile.java
@@ -714,7 +714,7 @@ public abstract class DotnetCompile
      * @param define
      */
     public void addDefine(Define define) {
-        definitionList.add(define);
+        definitionList.addElement(define);
     }