diff --git a/lib/java/build.xml b/lib/java/build.xml
index 75e7451..6f9d0b0 100644
--- a/lib/java/build.xml
+++ b/lib/java/build.xml
@@ -12,7 +12,7 @@
   </target>
 
   <target name="compile" depends="init">
-    <javac srcdir="${src}" destdir="${build}" />
+    <javac srcdir="${src}" destdir="${build}" source="1.5" />
   </target>
 
   <target name="dist" depends="compile">