RFR: 8368960: Adjust java UL logging in the build [v2]

[Erik Joelsson]

On Thu, 2 Oct 2025 07:55:18 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> > I thought the aim was to redirect log warnings/errors to stderr, not to disable logging completely.
> 
> Yeah I considered this too. But not sure about it ; bring the UL messages (warnings/errors etc.) really a benefit _in the build_ itself ? But I am open to set some other UL command line flags keeping messages .

If it's possible to redirect it to stderr, I think that would be preferred. It would make us aware of misconfigured tool command lines. 

In the case of the original warning you saw that triggered this, I think we need to actually fix our usage of CDS in the boot JDK. The current implementation was introduced back when the JDK didn't ship with a default CDS archive. Now that it does, we don't actually need to create one in configure. It would be interesting to see if there is any performance difference using the default archive.

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PR Comment: https://git.openjdk.org/jdk/pull/27588#issuecomment-3361176686