PL/Java 1.5.1

I expect to shortly tag a 1.5.1 release (just in time to say it builds
with PG 11).

I had a few last-minute thoughts about the .deb builds (in order of
outlandishness, maybe).

1. It looks as if they are being built with libjvmdefault => java 8.
Do some of the distro releases they are being built for have a later
version of Java as the default? (If I'm looking in the right places,
it seems that the Ubuntu default-jdk-headless is 8 for xenial and
artful, 10 for bionic, 11 for cosmic. Debian's default-jdk seems to
be 7 in wheezy and jessie, 8 in stretch, 10 in buster and sid,
11 in experimental).

It might be nice to build pljava packages where libjvmdefault => the
default version for the release. It still has to be /built/ with 8, but
can then run with the later versions on releases that have them. The
user can always set pljava.libjvm_location to a different version, but
this would have the property that leaving it alone means getting the
expected Java version, and (in recent releases) having access to newer
Java features, without having to take extra steps.

2. You seem to be building packages for PG from 11 back to 9.3. For that
range of PG versions, it would be possible to add the -Psaxon-examples
option on the build command (if you can stomach having the 5 MB
Saxon-HE-9.8.0.14.jar as a build dependency). The jar can be left out
of the package as an optional runtime dependency. The Saxon examples
would just be included in the pljava-examples jar, they would get
automatically loaded in PG if the user installs the jar. They wouldn't
work unless the user also installed the Saxon-HE jar, but that would be
the only step needed for someone who might want to try them.

It's actually safe to add -Psaxon-examples when building for any PG
version back to 8.4. Before 8.4, those examples can't be included
in pljava-examples.jar because their deployment SQL commands would
be syntax errors and prevent installing the jar, which is why I made
the build option.

3. Here is the possibly outlandish thought: I see in
pool/main/p/postgresql-pljava/ that there are existing .debs in there
for PG 9.2 back to 8.1, and they are based on really ancient PL/Java
versions with serious known bugs. I have been taking pains to make sure
PL/Java 1.5.x stays buildable back to 8.2 (but not 8.1, sadly). It would
be great if there could be packages in the repo so that those old buggy
ones would not be the only ones available. I understand that your build
arrangements probably don't even have those six PG versions present to
build against, and there is probably no justification for doing ongoing,
automated builds for them. Even if it were possible to just do one round
of builds and leave them there (as it appears those old packages are
simply left in the directory from years ago), that would benefit anyone
who needs, for some reason, to use such an old PG version.

Someone has actually opened a PL/Java issue this week who is using
PG 8.3. :) I did not press for details about why.... That's on Windows
though.

Cheers,
-Chap