diff --git a/java/external/build.xml b/java/external/build.xml
index 34059fd..6438dce 100644
--- a/java/external/build.xml
+++ b/java/external/build.xml
@@ -16,6 +16,9 @@
   <!-- Location of the system's temporary directory; all output sent here -->
   <property name="tmp.dir" value="." />
 
+  <!-- Properties to control compilation -->
+  <property name="debug" value="off"/>
+
   <!-- Build directories -->
   <property name="build.dir" value="${tmp.dir}/build" />
   <property name="build.classes.dir" value="${build.dir}/classes" />
@@ -65,7 +68,8 @@
 
   <target name="compile" depends="prepare"
     description="Compile all classes">
-   <javac srcdir="${src.dir}" destdir="${build.classes.dir}" />
+   <javac srcdir="${src.dir}" destdir="${build.classes.dir}"
+          debug="${debug}" />
   </target>
 
   <target name="jar" depends="compile"