diff --git a/include/jni_md.h b/include/jni_md.h
index 989dbfe..f7867d7 100644
--- a/include/jni_md.h
+++ b/include/jni_md.h
@@ -32,7 +32,7 @@ executable file might be covered by the GNU General Public License. */
 #define JNIEXPORT
 #define JNIIMPORT
 
-typedef unsigned char jboolean;
+typedef int jboolean;
 typedef signed char jbyte;
 typedef unsigned short jchar;
 typedef short jshort;