A question ad JDK 9 or: how to make all javax.script engines available to all Java apps in JDK 9?

[Tim Boudreau]

>
> Ad "not seeing a lot of usage": probably only those take advantage of the
> extension mechanism who
> have no alternative to it. So it would make sense that only a few use it,
> but for them it is
> probable, that it is of high importance.
>

I'll express some kudos for the removal of that.

Until you've worked full-time on an application where its users have random
undiagnosable bugs caused because some other application installed
something buggy into the JDK system-wide (ancient, broken versions of XML
parsers come to mind), you can't appreciate how horrific a mistake it was
to ever permit this sort of thing.

It was a mistake that it ever existed, probably caused by someone seeing
that that was the model for delivering libraries for Windows in the 90s and
thinking that made it an okay thing to do (dll-hell, anyone?).  It never
was, and there are decades of evidence to support that conclusion.

If OpenOffice or something else needs a list of scripting engines, it
should bundle what it needs, or provide a way for users to add more, and
make those available.  The idea of a magic JDK that grows new features
thanks to other applications installing stuff on the system is a recipe for
disaster.

For the applet scenario, if the server and client do their HTTP cache
headers right, there is no practical difference between loading a java
extension from disk somewhere in the JDK and using a previously downloaded
JAR cached by the browser from disk.

It really can't be overstated how bad an idea that was from day one - for
stability, for predictable behavior, for knowing what you're running
against and for security.

-Tim