On Feb 12, 2018, at 11:59 AM, Rony G. Flatscher <rony.flatsc...@wu.ac.at> wrote:
> While testing a rather complex one (an adaption of the JavaFX address book 
> example enhanced with a
> BarChart, [1]), that exhibits a very strange behavior: when setting the 
> values for the CategoryAxis
> supplying an ObservableList of the month names in the current Locale, using a 
> MethodHandle and
> invoking it with invokeWithArguments() would yield (debug output):

I just happened to see your message about your adventures with method handle:


This isn't really a jigsaw question, so I'm replying to mlvm-dev.

It looks like you are mixing or interconverting arrays of strings
with lists of strings.  The print statements and CCE show that
you are passing an array of strings into a place which expects
a single string, and the print statements suggest you are
in fact passing a list containing a string array into a place
which expects a list of strings.  Either way there are too
many brackets in your actual argument.

The prime suspect when the number of brackets is off by one
is varargs.  You code might be failing because of surprises
in the overload resolution of invokeWA, which accepts
a varargs Object array *and* a single List.

Is your runtime invoke mechanism treating invokeWA as an ordinary
method?  It is rather extraordinary, and may warrant a second look.

String str;
Object obj;
Object[] aobj;
String[] astr;
List lst;

plain single arity invocations:

1 mh.invokeWithArguments(str) => new Object[] { str }
2 mh.invokeWithArguments(obj) => new Object[] { obj }

and yet:

3 mh.invokeWithArguments(aobj) => aobj (multiple args)
4 mh.invokeWithArguments(astr) => astr (multiple args again!)
5 mh.invokeWithArguments(lst) => lst.toArray() (multiple args again!)

but again, a cast removes varargs:

6 mh.invokeWithArguments((Object) aobj) => new Object[] { aobj }
7 mh.invokeWithArguments((Object) astr) => new Object[] { astr }
8 mh.invokeWithArguments((Object) lst) => new Object[] { lst }

Your bug looks like a confusion between two of these,
perhaps 5 and 8.

— John

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