RFR: JDK-8189094: Change required boot jdk to JDK 9

[Alan Bateman]

On 16/10/2017 19:53, Martin Buchholz wrote:
> What's the canonical way to list all upgradeable modules?
> There's a list in JEP 261, but naturally we can't consider it 
> authoritative.
make/common/Modules.gmk has the list (look for UPGRADEABLE_MODULES and 
UPGRADEABLE_TOOL_MODULES).

>
> I was surprised that even java --describe-module doesn't tell me 
> whether a module is upgradeable.
All non-core modules (meaning modules not associated with the boot 
loader) are upgradable unless tied by hashes to java.base. So you need 
to look at java.base to find the list of modules that it has recorded 
hashes for. `javap -v -m java.base module-info` is one way to see this. 
Not very user friendly but upgradeable modules aren't broadly 
interesting to joe developer. If joe developer is interested then the 
javadoc for each of the upgradable modules has a statement in its 
javadoc to say this. The equivalent with Java SE 8 / JDK 8 and older was 
the table of APIs and JSR in the Endorsed Standards Override Mechanism 
document.

>
> I was surprised to see JEP 261 say that java.compiler is upgradeable, 
> but not jdk.compiler.
> Perhaps thinking of the bootstrap use case?
I see Jon has replied to this point. Another part to that is that 
java.compiler exports the APIs maintained by JSR 199 and JSR 269 and 
these two JSR remain standalone technoloiges.

-Alan.