--- jsr166/build.xml	2013/02/01 21:58:27	1.132
+++ jsr166/build.xml	2013/02/03 02:16:08	1.133
@@ -249,6 +249,7 @@ As of 2013-02, the very latest lambda 8
            fork="true">
 
       <include name="**/*.java"/>
+      <compilerarg value="-Xprefer:source"/>
       <compilerarg value="-XDignore.symbol.file=true"/>
       <compilerarg value="-Xlint:all"/>
       <compilerarg line="${build.args}"/>
@@ -590,6 +591,7 @@ As of 2013-02, the very latest lambda 8
            fork="true">
 
       <include name="**/*.java"/>
+      <compilerarg value="-Xprefer:source"/>
       <compilerarg value="-XDignore.symbol.file=true"/>
       <compilerarg value="-Xlint:all"/>
       <compilerarg line="${build.args}"/>