diff --git a/external/stoken/java/build.xml b/external/stoken/java/build.xml
index ded2a76..5f821bb 100644
--- a/external/stoken/java/build.xml
+++ b/external/stoken/java/build.xml
@@ -5,6 +5,8 @@
 
 	<property name="jar_lib" location="${dist}/stoken-wrapper.jar"/>
 	<property name="jar_app" location="${dist}/example.jar"/>
+	<property name="ant.build.javac.source" value="1.7"/>
+	<property name="ant.build.javac.target" value="1.7"/>
 
 	<target name="init">
 		<mkdir dir="${build}"/>