JOSM update from http://josm.openstreetmap.de/apt precise universe fails on Ubuntu 12.04

[SomeoneElse2]

JOSM 10526 on Ubuntu 12.04 has previously used /usr/lib/jvm/java-7-openjdk-i386/bin/java .

apt-get-install josm

Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.

josm : Depends: openjdk-8-jre but it is not installable or

java8-runtime but it is not installable

E: Unable to correct problems, you have held broken packages.

JOSM's front screen merely says "You should update". It doesn't say how.

[Don-vip]

Ubuntu 12.04 is severely outdated, please either:

• upgrade to 16.04.1 LTS (recommended)
• stick to the last Java 7 version (r10526) as described there: ​http://askubuntu.com/a/18656/269967

[SomeoneElse2]

You are wrong; it is not severely outdated - see ​https://wiki.ubuntu.com/LTS for details (it's supported by Ubuntu until the back end of next year). You may choose not to allow JOSM to run on current supported Linux versions of course; that's entirely your choice - but please be aware that that is what you are doing.

[Don-vip]

The "support" Canonical offers with old LTS concerning Java is a joke, see ​https://bugs.launchpad.net/trusty-backports/+bug/1368094: they never add new versions of Java.

If you want to use latest JOSM, Java 8 is needed, but if you want to stay on an old distribution that does not provide it, you will have to find a way to install it manually, with a PPA or something.