Hi,
I've spend half of a day trying those new features of manifest file
that r claimed to be supported in JRE1.3RC3. And the results r ...
encouraging! First of all, native installers ARE supported. That is u
wrap .exe installer of J3D into a signed jar file, put appropriate
line into manifest file and here u go! - plugin downloads the jar,
executes the installer, waits 4 it to complete and continues
flawlessly to run the applet. So, finally, there are no more questions
about J3D distribution. But as to the other extensions that r shipped
without any installers (like vrml97.jar), i'm afraid there is a
problem here. Plugin, upon downloading signed jar, asks u weather u
want to install/run ..... U answer 'Grant...' and... nothing happens.
That is jar is not put to ext dir. But when u wrap, lets say,
vrml97.jar into ANOTHER jar (eg, vrml97Wrapped.jar) and sign that jar,
the extension normally downloads and u r NOT asked to install/run
..... The next moment u find the jar at your ext dir. But the problem
is that it is NOT vrml97.jar, but vrml97Wrapped.jar that u find there,
so there is little use in it, since VM can't find the 'double-packed'
classes. I've tried to overcome the problem this and that way, but
nothing actually helped to fix this. I doubt i did anything wrong,
but... who knows.
So, as a summary, downloadable extension mechanism finally works, but
there are some bugs (simply overridable though - just write your own
java installer that would put files into ext dir). For those ones who wanna
play around and try the mechanism him/her- self, at
http://java.sun.com/products/jdk/1.3/docs/guide/extensions/versioning.html
u'd find some useful information. U can also take a look at JAR spec
at http://java.sun.com/products/jdk/1.3/docs/guide/jar/jar.html.
I also attached manifest file i used to wrap java3d installer into
.jar archive.
All the best, further information on 'normal' extensions (like
vrml97.jar) downloading would be highly appreciated. And if it is a
bug (Sun guys, is it really?), let us know as well, so that we
wouldn't spend time in vain attempts to achieve unachievable.
Bye,
vladimir
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