I posted here (before creating a ticket somewhere) in case I missed something obvious about current java (JRE) version, OpenWebStart or Windows environment.
The context: This morning I started JOSM using OpenWebStart. I was prompted to update JOSM. Following instructions I downloaded and ran JOSM.JNLP. I got the expected warning messages about untrusted website and accepting to run JOSM from an unknown publisher. Nothing really new.
The problem: I get a warning that the application uses a version of Java (+11) that is not installed on my system. If I click on “run with the latest version” (in my case the “official” Java JRE 8), I get an exception error saying something like: … needs a class file version 55.0, while my version of java only recognizes version 52.0.
It sounds like you’ll need to update the Java Virtual Machine (JVM) version that OpenWebStart is using. It has a built in JVM manager for doing this. Personally, I got tired of messing around with OpenWebStart and the confusing Java version situation after v8 (caused by the Oracle licensing mess). Now I just use the JOSM installers that come with their own bundled Java version so I don’t have to think about it. I miss automatic updates, but they don’t come so often that it’s a huge issue.
Thanks, I just used josm-setup.msi and it worked fine.
I was using the Windows JOSM installer until JOSM recommended a web installer, but I’m going back to the MSI. The Windows Store version is outdated and requires some manipulation I’m unfamiliar with.
Regarding Java, I received a similar error message a few weeks ago when trying to install Osmosis. Would it be possible for OSM developers to explain/document (for novice users like me) how to run Java apps that are not compatible with Oracle’s Java 8 JRE?