JOSM is not starting after installation

[alf.hamann@…]

After installation on Mac Air 2012 and High Sierra (OS 10.13.6), JOSM 14460 is not working but giving the error message:
Fehler beim Initialisieren des Tests ApiCapabilitiesTest: "org.openstreetmap.josm.io.OsmApiInitializationException: org.xml.sax.SAXNotRecognizedException: ​http://javax.xml.XMLConstants/feature/secure-processing"
Actual version of Java 8 should be installed and activated in browser and system, as far as I can see.

[Don-vip]

Whats does java -version say?

[alf.hamann@…]

Hi, thanks for the rapid response.
Installed version version of Java is: 8-Update 191.
More info regarding the behavior upon opening: JOSM is starting, but upon loading of a file, the error described above is indicated. (Note: the file might be too large (2.5 GB), but I guess this is not the reason for the error message). If the error message is ignored and I start downloading a map from the file menu, another error message is displayed: "Initialisation of communication with OSM-Server ​https://api.openstreetmap.org/api has failed. Please check server URL in preferences and internet connection".
Best
Alf

[Don-vip]

It means there's a problem with your Internet access. But we cannot guess remotely what the problem is.

[alf.hamann@…]

Replying to Don-vip:
No problem with internet connection; I simultaneously logged in successfully into OSM (outside of JOSM), but also this did´nt change the error messages. So, I gave up after investing several hours...

[anonymous]

The program starts properly on a different user account on the same Mac, without any error message. So, something in the user/library must be contain a bug.