RFR(S): 8075253: Multiversion JAR feature: CDS does not support MV-JARs

[Steve Drach]

Yes, it’s a bug.  I’m currently working on another bug that requires me to change manifest processing.  It will be case insensitive.

> On Mar 19, 2016, at 10:24 AM, Calvin Cheung <calvin.cheung at oracle.com> wrote:
> 
> 
> 
> On 3/19/16, 12:41 AM, Alan Bateman wrote:
>> 
>> 
>> On 18/03/2016 23:38, Claes Redestad wrote:
>>> Hi,
>>> 
>>> sorry for being a bit out of the loop, but according to the most recent published spec[1] I could find the manifest attribute names needs to be treated case-insensitively. Has JEP-238 made necessary specification updates to allow deviation from this rule for new attribute names?
>> Good point, attributes names have always been case insensitive. I don't recall anything in JEP 238 that proposes otherwise.
> 
> Currently, the jdk code only honors "Multi-Release" as the attribute name for multi-release jar.
> 
> I ran the following test: jdk/test/jdk/nio/zipfs/MultiReleaseJarTest.java
> 
> It created a multi-release.jar.
> Running the jar file manually:
> java -cp ./multi-release.jar version.Main
> gives the following output:
> I am running on version 9
> 
> Then, I expanded the jar file and modified the manifest entry from "Multi-Release" to "multi-Release" and created another jar file.
> Running the new jar file shows:
> I am running on version 8
> 
> The code in JarFileSystem.java seems to confirm my findings:
> 
>    private boolean isMultiReleaseJar() {
>        try (InputStream is = newInputStream(getBytes("META-INF/MANIFEST.MF"))) {
>            return (new Manifest(is)).getMainAttributes()
>                    .containsKey(new Attributes.Name("Multi-Release"));
>            // fixme change line above after JarFile integration to contain Attributes.Name.MULTI_RELEASE
>        } catch (IOException x) {
>            return false;
>        }
>    }
> 
> To be consistent, I think hotspot should wait until jdk side has a fix to handle case insensitive "Multi-Release" attribute name.
> 
> What do you think?
> 
> thanks,
> Calvin
>