Jigsaw classpath mode support

[Mandy Chung]

On 8/15/2012 11:05 AM, Alan Bateman wrote:
> On 07/08/2012 18:47, Mandy Chung wrote:
>> I have implemented the "classpath mode" support running on
>> a module image.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~mchung/jigsaw/webrevs/classpath-mode.00/
> I've finally got through all of this. Overall this is really good work.
>

Thanks for the review.

> A couple of comments/questions:
>
> In ClassPathContext when you distribute the contexts to each loader 
> then it may be more efficient to iterate over each loader's module 
> list and invoke the configuration's getContextForModuleName to get the 
> Context directly. Then distribute the remaining to the loader for the 
> boot class path. I suspect that could be more efficient than all the 
> nested contains.
>

You are referring to L209-222, right?  This is a good suggestion.   I'll 
revise it.

> One thing that I can't tell from the changes is the value of the 
> sun.boot.module.classpath property. That might be clear once Karen 
> publishes the hotspot changes. I ask because I can't tell if 
> Package.SystemPackage.isPackageFromModule is right, meaning whether 
> JVM_GetSystemPackage returns the value of sun.boot.module.classpath 
> for packages in the system modules.
>
Yes, JVM_GetSystemPackage will return the value of 
sun.boot.module.classpath for packages in the system modules.  It's a 
simple way to tag a package in the system module.

> In Launcher. ExtClassLoader there is code to split the extension 
> directory into the paths that come before and after the default 
> location. I think I need help in understand why someof this is needed 
> because if someone sets java.ext.dirs then it should be a complete 
> override?
>

It's for searching native libraries from the module image or 
user-specified ext dir.  The ExtClassLoader overrides the findLibrary 
method.   The java.ext.dirs can be overridden in the command line; if 
not set, the VM will set its value to the default ext dirs.  In 
addition, someone can set java.ext.dirs to include JAVA_HOME/lib/ext 
plus other additional directory.   If the default ext dir is inclued in 
the java.ext.dirs, ExtClassLoader needs to locate the native library 
from the module image and loads a native library from each directory 
specified in the property value before and after the default.

> I agree with your idea in the mail to get this pushed and deal with 
> any clean-up/comments in later changes, especially as the test results 
> are good. The only thing is I assume it will need to go in with the 
> HotSpot changes.
>
> In terms of clean-up then I think CleanPathContext should be more 
> efficient. There are also a few things in the sun.misc.Launcher code 
> but they aren't urgent for now.
>

I'll fix the ClassPathContext how it distributes the modules/contexts to 
each loader.  Let me know what other things you have in mind and I will 
see if I should fix them together.

Thanks
Mandy