NPE: Cannot invoke "java.util.Collection.isEmpty()" because "existing" is null

[anonymous]

What steps will reproduce the problem?

What is the expected result?

What happens instead?

Please provide any additional information below. Attach a screenshot if possible.

Revision:18531
Build-Date:2022-08-02 12:45:38

Identification: JOSM/1.5 (18531 pl) Windows 10 64-Bit
OS Build number: Windows 10 Home 2009 (19044)
Memory Usage: 280 MB / 1768 MB (30 MB allocated, but free)
Java version: 17.0.4+8-LTS, Azul Systems, Inc., OpenJDK 64-Bit Server VM
Look and Feel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Screen: \Display0 1920×1080 (scaling 1.00×1.00)
Maximum Screen Size: 1920×1080
Best cursor sizes: 16×16→32×32, 32×32→32×32
System property file.encoding: Cp1250
System property sun.jnu.encoding: Cp1250
Locale info: pl_PL
Numbers with default locale: 1234567890 -> 1234567890
VM arguments: [-Djpackage.app-version=1.5.18531, --add-modules=java.scripting,java.sql,javafx.controls,javafx.media,javafx.swing,javafx.web, --add-exports=java.base/sun.security.action=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED, --add-opens=java.base/java.lang=ALL-UNNAMED, --add-opens=java.base/java.nio=ALL-UNNAMED, --add-opens=java.base/jdk.internal.loader=ALL-UNNAMED, --add-opens=java.base/jdk.internal.ref=ALL-UNNAMED, --add-opens=java.desktop/javax.imageio.spi=ALL-UNNAMED, --add-opens=java.desktop/javax.swing.text.html=ALL-UNNAMED, --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED, -Djpackage.app-path=%UserProfile%\AppData\Local\JOSM\JOSM.exe]

Plugins:
+ ColumbusCSV (35978)
+ FastDraw (35978)
+ OpeningHoursEditor (35924)
+ PicLayer (1.0.2)
+ apache-commons (36003)
+ buildings_tools (36011)
+ changeset-viewer (v0.0.6)
+ continuosDownload (99)
+ ejml (35924)
+ fieldpapers (v0.5.0)
+ geotools (36015)
+ gridify (1606242219)
+ jackson (36006)
+ jaxb (35952)
+ jts (36004)
+ measurement (35978)
+ merge-overlap (35893)
+ plbuildings (1.7.0)
+ reverter (36011)
+ tageditor (36011)
+ terracer (35978)
+ turnlanes-tagging (v0.0.5)
+ turnrestrictions (36011)
+ undelete (36011)
+ utilsplugin2 (36011)

Tagging presets:
+ https://josm.openstreetmap.de/josmfile?page=Presets/OpenTollMap&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/LaneAttributes&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Presets/Maxspeed-zones&zip=1
+ https://raw.githubusercontent.com/yopaseopor/traffic_signs_preset_JOSM/master/PL.zip
+ https://josm.openstreetmap.de/josmfile?page=Presets/Tracks&zip=1
+ C:\Program Files\qCliks.zip

Map paint styles:
- https://raw.githubusercontent.com/yopaseopor/indoormap/master/indoormap-style.mapcss
- https://josm.openstreetmap.de/josmfile?page=Styles/ColorWays&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ColourTag&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Enhanced_Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/FixmeAndNote&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Styles/iD&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PriorityRoad&zip=1

Last errors/warnings:
- 00000.982 W: extended font config - overriding 'filename.Myanmar_Text=mmrtext.ttf' with 'MMRTEXT.TTF'
- 00000.985 W: extended font config - overriding 'filename.Mongolian_Baiti=monbaiti.ttf' with 'MONBAITI.TTF'
- 00003.549 E: java.security.KeyStoreException: Windows-ROOT not found. Przyczyna: java.security.NoSuchAlgorithmException: Windows-ROOT KeyStore not available
- 00018.149 E: Nie udało się zlokalizować obrazu „'
- 00018.151 W:  qCliks: Could not get presets icon 
- 00018.162 E: Nie udało się zlokalizować obrazu „'
- 00018.163 W:  Driveway: Could not get presets icon 
- 00018.166 E: Nie udało się zlokalizować obrazu „'
- 00018.167 W:  Reedbed: Could not get presets icon 
- 00059.682 E: Handled by bug report queue: java.lang.NullPointerException: Cannot invoke "java.util.Collection.isEmpty()" because "existing" is null



=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: Timer-0 (55)
java.lang.NullPointerException: Cannot invoke "java.util.Collection.isEmpty()" because "existing" is null
	at org.openstreetmap.josm.plugins.continuosDownload.AbstractDownloadStrategy.fetch(AbstractDownloadStrategy.java:33)
	at org.openstreetmap.josm.plugins.continuosDownload.AbstractDownloadStrategy.fetch(AbstractDownloadStrategy.java:27)
	at org.openstreetmap.josm.plugins.continuosDownload.DownloadPlugin$Task.run(DownloadPlugin.java:140)
	at java.base/java.util.TimerThread.mainLoop(Unknown Source)
	at java.base/java.util.TimerThread.run(Unknown Source)

[taylor.smock]

Fixed in ​09d50a5fc1fd680b56ea5a8257b565b820e3656f. I'll merge the other open PR's for it, and try to get a release out today.

[taylor.smock]

Ticket #21729 has been marked as a duplicate of this ticket.