Small VM change for booting from a module

[Karen Kinnear]

Mark,

Thanks for doing this. A couple of minor questions/comments.

It appears that meta_index_path and meta_index_dir are by
default NULL. I'm not sure what happens on different OSs when  
classLoader.cpp: setup_meta_index
calls fopen(meta_index_path, "r") and passes in a null. You might be
safer initializing those values in os::set_boot_path.

I'm assuming you want to deal with Class Data Sharing compatibility
after J1. If it helps to model usage of the new property, today CDS  
requires that
the bootclasspath contain individual jars, not lists of directories,  
to reduce
having to check timestamp and file size for all .class files, and reduce
startup costs.

If you want to know what the vm  is using
for the sysclasspath you can run with -XX:+TraceClassLoading -XX: 
+Verbose,
if you are running fastdebug.

Also, there is a comment in ClassLoader.cpp you might want to check  
into:
... doesn't reorder the bootclasspath which would break  
java.lang.Package (see PackageInfo).

thanks,
Karen

On May 14, 2009, at 12:38 PM, Mark Reinhold wrote:

> I've made a small VM change to support booting from a module.  At the
> moment it's a bit like the old settable sun.boot.class.path, but I've
> put "module" in its name because it will, most likely, eventually have
> semantics beyond just setting the boot path.
>
> Webrev: http://cr.openjdk.java.net/~mr/vm-module-boot
>
> Karen -- Okay to push?
>
> - Mark