Review request: 8157068 ExceptionInInitializerError if images build patched to use exploded version of java.lang.module.SystemModules

[Alan Bateman]

On 19/05/2016 02:41, Mandy Chung wrote:
> Webrev at:
>    http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8157068/webrev.00/index.html
>
> This is to allow to patch java.base with an exploded image for JDK development purpose like this:
> $ images/jdk/bin/java -Xpatch:java.base=jdk/modules/java.base -version
>
> jdk.internal.module.SystemModules class is generated at link time to allow fast reconstitution of ModuleDescriptor.  If an image is patched with java.base of an exploded image, it will fall back to read and parse module-info.class from the jimage.  Hashes of tied modules are recorded in jdk.internal.module.SystemModules class in the fast path.  If patched, this fix will use the hashes recorded in the Hashes attribute for integrity check (that already validated at link time).
>
A complicated scenario but the approach looks okay. No need to use 
JavaLangModuleAccess to get at the hashes, just use descriptor.hashes().

The patch test directory already has a basic test for -Xpatch and might 
be confusing to have the modules for both tests in the same tree. I 
wonder if we should move each both tests in their own sub-directory to 
keep it easier to understand.

-Alan.