diff --git a/Lib/java/javahead.swg b/Lib/java/javahead.swg
index 872d56d7a..cc1592395 100644
--- a/Lib/java/javahead.swg
+++ b/Lib/java/javahead.swg
@@ -36,6 +36,7 @@
 #include <jni.h>
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 %}
 
 %insert(runtime) %{