private static Object toJava(Varargs v) {
   final int n = v.narg();
   switch (n) {
     case 0:
       return null;
     case 1:
       return toJava(v.arg1());
     default:
       Object[] o = new Object[n];
       for (int i = 0; i < n; ++i) o[i] = toJava(v.arg(i + 1));
       return o;
   }
 }