NPE at AbstractTileSourceLayer.getVisibleTileSet

[anonymous]

What steps will reproduce the problem?

1. Open OpenStreetCam layer (opens automatically on my setup)
2. Open Bing imagery
3. Close OSC and then Bing imagery

What is the expected result?

Bing imagery goes away and JOSM returns to welcome screen

What happens instead?

Exception. Probably only sporadically.

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

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2019-03-03 00:16:03 +0100 (Sun, 03 Mar 2019)
Build-Date:2019-03-02 23:16:53
Revision:14824
Relative:URL: ^/trunk

Identification: JOSM/1.5 (14824 en) Linux Ubuntu 18.10
Memory Usage: 892 MB / 1820 MB (122 MB allocated, but free)
Java version: 1.8.0_201-b09, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: :0.0 1680x1050
Maximum Screen Size: 1680x1050
VM arguments: [-Djava.security.policy=file:${JAVA_HOME}/jre/lib/security/javaws.policy, -DtrustProxy=true, -Djnlpx.home=${JAVA_HOME}/jre/bin, -Djava.security.manager, -Djnlpx.origFilenameArg=${HOME}/.java/deployment/cache/6.0/56/1ee8cfb8-2f914bf0, -Djnlpx.remove=false, -Dsun.awt.warmup=true, -Djava.util.Arrays.useLegacyMergeSort=true, -Djnlpx.heapsize=NULL,2048m, -Djnlpx.splashport=40317, -Djnlp.application.href=https://josm.openstreetmap.de/download/josm.jnlp, -Djnlpx.jvm=${JAVA_HOME}/jre/bin/java]

Plugins:
+ OpenStreetCam (184)
+ buildings_tools (34904)
+ utilsplugin2 (34867)

Map paint styles:
+ https://josm.openstreetmap.de/josmfile?page=Styles/TigerReviewedNo&zip=1

Last errors/warnings:
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- E: Handled by bug report queue: java.lang.NullPointerException


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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-2 (56) of javawsApplicationThreadGroup
java.lang.NullPointerException
	at org.openstreetmap.josm.gui.layer.AbstractTileSourceLayer.getVisibleTileSet(AbstractTileSourceLayer.java:903)
	at org.openstreetmap.josm.gui.layer.AbstractTileSourceLayer.loadAllErrorTiles(AbstractTileSourceLayer.java:930)
	at org.openstreetmap.josm.gui.layer.TMSLayer.lambda$getTileSource$0(TMSLayer.java:74)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

[Don-vip]

In 14902/josm:

fix #17481 - NPE