diff -ur apache-ant-1.6.2.orig/src/main/org/apache/tools/ant/taskdefs/Javac.java apache-ant-1.6.2/src/main/org/apache/tools/ant/taskdefs/Javac.java
--- apache-ant-1.6.2.orig/src/main/org/apache/tools/ant/taskdefs/Javac.java	2005-06-11 01:02:41.000000000 +0200
+++ apache-ant-1.6.2/src/main/org/apache/tools/ant/taskdefs/Javac.java	2005-06-11 01:25:47.000000000 +0200
@@ -148,6 +148,9 @@
      * @return value of source.
      */
     public String getSource() {
+        if (source==null) {
+            return getProject().getProperty("build.source");
+        }
         return source;
     }
 
@@ -573,6 +576,9 @@
      * @return the target VM
      */
     public String getTarget() {
+        if (target==null) {
+            return getProject().getProperty("build.target");
+        }
         return target;
     }