I am beginning to feel like people are putting words in my mouth :)
I agree with most of what you said. I will only comment on the differences:
There is nothing special in java, that's just another language like perl, python and tcl. I don't see any reason to treat that differently.
I don't disagree per-se. I think bundling the JRE would help users, but it's a tiny problem compared to needing to build pl/java from source. If we can fix the latter, the former is a smaller issue. Sidenote: when I talk about "bundling" the JRE I simply mean adding an option in the installer to download and unpack it on behalf of the user.
Adding an option to the installer is something else than adding the jre into the core. Installer for windows can install many different things which are not in the core. The linux installer is another thing, I'm not using an installer, I've got debs in repository, having one more package for the pljava is not a bad idea. However another package is not the same as jre in the core postgres.
As far as I remember the windows installer can also install postgis, which definitely is not a part of postgres, but it's an external library.
I think all people here agree that adding another package to linux repository or an option to windows installer is OK. What some people disagree here is adding jre to the core postgres.
Oh, and btw, I've got a package named postgresql-9.3-pljava-gcj in my linux repo.
If there is a programmer who cannot install jvm/jdk on its own (which is a couple of clicks on windows and linux) then I'm sure that writing stored procerures in java will be even too difficult.
Installing a public JVM is easy. Binding it to pl/java is not. By bundling a private JRE we control the default installation path and can therefore pre-configure pl/java to look for it in that location.
The best solution would be to make different languages, like pljava6, pljava7, pljava8, with library path configured in the create extension command. This way we could use different jvms and library versions for each database.
But this still doesn't mean adding jre to the core postgres.
I'm not taking this option away from you. Power users can still do what they want. I'm just trying to facilitate deployment users who are fine with the default/typical configuration.
So in fact you propose to create another option in the windows installer only, right?