diff --git a/docs/manual/CoreTasks/javac.html b/docs/manual/CoreTasks/javac.html
index 7e70e7e9f..6a2e9701f 100644
--- a/docs/manual/CoreTasks/javac.html
+++ b/docs/manual/CoreTasks/javac.html
@@ -341,6 +341,8 @@ invoking the compiler.</p>
   <tr>
     <td valign="top">tempdir</td>
     <td valign="top">Where Ant should place temporary files.
+      This is only used if the task is forked and the
+      command line args length exceeds 4k.
       <em>Since Ant 1.6</em>.</td>
     <td align="center" valign="top">No; default is the current working
        directory.</td>