JOSM offline slow startup

I need to run JOSM on a Machine without a connection to the Internet.
When there is no Internetconnection JOSM starts really slow. After starting JSOM it takes about 30sec where nothing seems to happen until the splashscreen appears.

When starting JOSM in Commandprompt it turns out that 25sec of the 30sec JOSM tries to request certificates.

I have found the parameter “–offline=…” to use when working offline. But during startup this does nothing change. JOSM still needs 30sec until the splashscreen appears and it still requests certificates.

Here all Information I see in the commandprompt:

C:\Users\user>java -jar "D:\JOSM\josm-tested.jar" --offline=all
2019-04-18 09:32:35.122 INFO: Log level is at INFO (INFO, 800)
2019-04-18 09:32:35.310 WARNING: JOSM is running in offline mode. This resource will not be available: ALL
2019-04-18 09:32:40.929 WARNING: Unable to request certificate of https://roottest-g2.pkioverheid.nl
2019-04-18 09:32:46.031 WARNING: Unable to request certificate of https://roottest-g3.pkioverheid.nl
2019-04-18 09:32:51.119 WARNING: Unable to request certificate of https://www.certigna.fr
2019-04-18 09:32:56.211 WARNING: Unable to request certificate of https://eidas.disig.sk
2019-04-18 09:33:01.332 WARNING: Unable to request certificate of https://grca.nat.gov.tw
2019-04-18 09:33:03.151 WARNING: OSM API not available (offline mode)
2019-04-18 09:33:03.154 WARNING: org.openstreetmap.josm.io.OfflineAccessException: Unable to access 'https://josm.openstreetmap.de/maps%<?ids=>': JOSM website not available (offline mode)
2019-04-18 09:33:03.169 SEVERE: java.io.IOException: Unable to get cache file for https://josm.openstreetmap.de/maps
2019-04-18 09:33:04.449 WARNING: OSM API not available (offline mode)
2019-04-18 09:33:04.620 WARNING: No configuration settings found.  Using hardcoded default values for all pools.
2019-04-18 09:33:04.674 WARNING: Region [TMS_BLOCK_v2] Resetting cache
2019-04-18 09:33:04.705 INFO: Message notifier not available (offline mode)
2019-04-18 09:33:04.706 INFO: Changeset updater active (checks every 60 minutes if open changesets have been closed)

Tested on:

  • JOSM: 14945
  • Java: 1.8.0_195
  • Windows Server 2016

Is there a way to speed up JOSM-startup when working without an internetconnection?

Please report this a bug using Help->Report Bug.

Here we go: #17619 offline startup slow

As mentioned in #17619 offline startup slow there is also a parameter “certificates” for the option “–offline=”

All options and parameters are listed in the JOSM-Wiki: Command Line Options