RFR: JDK-8200083: Bump bootjdk requirement for JDK 11 to JDK 10

[Ao Qi]

2018-03-22 6:41 GMT+08:00 John Paul Adrian Glaubitz
<glaubitz at physik.fu-berlin.de>:
> On 03/22/2018 07:07 AM, Martin Buchholz wrote:
>> But for users, being able to bootstrap with an ancient jdk is definitely
>> convenient.
>
> Convenient is an understatement. Always enforcing the N-1 version to be
> used can be quite painful for downstream distributions. Rust upstream
> does the same thing and it becomes very frustrating when bootstrapping
> the compiler.
>
> When, for example, an architecture has fallen back a couple of releases
> of OpenJDK, I would have to go through the whole chain of 8->9->10->11
> to get the latest OpenJDK. I know that cross-compiling is possible, but
> it's not always the easiest option.
>

Indeed. I was trying to build OpenJDK 11 zero on MIPS. Because I only had
OpenJDK 8 binary as boot JDK, I have to build OpenJDK 9 first.
It is even more painful when I build OpenJDK 11 32 bits zero. Because I only
have 32-bit OpenJDK 6 as boot JDK, I have to build 7, 8, 9 and then 11.

> So, from a downstream perspective, allowing the oldest possible version
> is always a desirable feature to have. I do understand it though when
> OpenJDK 11 requires features from OpenJDK 10 which would rule out older
> versions completely.
>
> Adrian
>
> --
>  .''`.  John Paul Adrian Glaubitz
> : :' :  Debian Developer - glaubitz at debian.org
> `. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
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