Project Jigsaw goals and requirements

[Michael Bien]

On 06/02/2011 05:30 PM, Richard S. Hall wrote:
> On 6/2/11 11:07, Benoît Thiébault wrote:
>> Hi everyone,
>>
>> This discussion about Jigsaw requirements is very interesting and
>> constructive and I am really looking forward to see what Java modules
>> will be capable of.
>>
>> Just to add my own set of remarks, I would like to point that support
>> for native librairies is very important and should not be neglected.
>>
>> In OSGi, it is already feasible, but it is poorly documented and has
>> some very strong constraints (as explained here:
>> http://dev.artenum.com/blog/ben/posts/osgi_vtk_and_macosx). One of the
>> most annoying things is to have to explicitly call System.loadLibrary()
>> for every shared library and its dependencies to tell OSGi framework
>> what .so (.dll or .jnilib) files to extract from the jar bundle.
>
> To be precise, this is not really an OSGi issue, but a more general 
> one about native library dependencies...Java can only intercept native 
> library load requests coming from Java code. Arbitrary native 
> libraries that have dependencies on other native libraries cannot be 
> intercepted by Java and automatically loaded by the JVM. The procedure 
> you describe above is simply a workaround.

there is a second problem which native libs: If i remember correctly you 
can load a lib only once per JVM instance but the scope of the lib is 
still the classloader. So what everyone did before java 6 got improved 
jnlp support for native libs was to copy the lib into /tmp, rename it 
and load it from there. Thats also one of the reasons why there is/was a 
master-slave jvm when running applets in the new browser plugin as far 
as I know.

Would be nice if jigsaw could handle that properly this time. E.g 
allowing two versions of the same library in one JVM etc.

best regards,
michael

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