crash with many picture meta data loaded, wasn't actively using JOSM though

[Polyglot]

What steps will reproduce the problem?

1. load too big an area, semi-automatic mode, JOSM was already sluggish
2. go chat with Jorge
3. out of the blue, the error message

What is the expected result?

What happens instead?

INFO: GET ​https://api.openstreetmap.org/api/0.6/map?bbox=4.698329,50.8344498,4.7
002816,50.8360929
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=WMS]
INFO: Silent shortcut conflict: 'properties:recent:11' moved by 'Mapillary' to '
Ctrl+Alt+F3'.
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=WMS]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=WMS]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=TMS]
INFO: GET ​https://api.openstreetmap.org/api/0.6/map?bbox=4.6976638,50.8359405,4.
6993482,50.8384271
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=WMS]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=WMS]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=mapillary]
[INFO] CacheEventQueue - Cache event queue created: CacheEventQueue [listenerId=
286503318, cacheName=WMS]
INFO: GET ​https://api.openstreetmap.org/api/0.6/user/details (get number of unre
ad messages)
ERROR: java.lang.NullPointerException
java.lang.NullPointerException

at org.glassfish.json.JsonObjectBuilderImpl$JsonObjectImpl.getString(Jso

nObjectBuilderImpl.java:199)

at org.openstreetmap.josm.plugins.mapillary.downloads.MapillaryTrafficSi

gnDownloaderThread.run(MapillaryTrafficSignDownloaderThread.java:70)

at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

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

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2015-08-09 01:33:01
Last Changed Author: wiktorn
Revision: 8651
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Relative URL: ^/trunk
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2015-08-08 19:58:08 +0200 (Sat, 08 Aug 2015)
Last Changed Rev: 8651

Identification: JOSM/1.5 (8651 en) Windows 7 64-Bit
Memory Usage: 828 MB / 1111 MB (230 MB allocated, but free)
Java version: 1.7.0_40, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Dataset consistency test: No problems found

Plugins:
- AddrInterpolation (31241)
- ImportImagePlugin (31241)
- Mapillary (31395)
- OpeningHoursEditor (31241)
- PicLayer (31241)
- RoadSigns (31241)
- TombPlugin (44)
- alignways (31241)
- buildings_tools (31361)
- commons-imaging (31241)
- contourmerge (1013)
- dataimport (31241)
- easy-routes (UNKNOWN)
- fieldpapers (v0.3.0)
- geochat (31241)
- geotools (31126)
- importvec (31241)
- jna (31126)
- jts (31126)
- livegps (31241)
- log4j (31231)
- mapdust (31241)
- measurement (31289)
- mirrored_download (31294)
- opendata (31241)
- pdfimport (31241)
- photo_geotagging (31241)
- photoadjust (31413)
- public_transport (31241)
- reverter (31241)
- scripting (30710)
- tag2link (31241)
- terracer (31241)
- todo (29154)
- turnrestrictions (31241)
- undelete (31241)
- utilsplugin2 (31241)
- walkingpapers (31241)
- wikipedia (31241)

Last errors/warnings:
- E: java.net.UnknownHostException: api.openstreetmap.org
- W: org.openstreetmap.josm.io.OsmTransferException: Could not connect to the OSM server. Please check your internet connection.. Cause: java.net.UnknownHostException: api.openstreetmap.org
- E: java.net.UnknownHostException: api.openstreetmap.org
- W: org.openstreetmap.josm.io.OsmTransferException: Could not connect to the OSM server. Please check your internet connection.. Cause: java.net.UnknownHostException: api.openstreetmap.org
- E: java.lang.NullPointerException

java.lang.NullPointerException
	at org.glassfish.json.JsonObjectBuilderImpl$JsonObjectImpl.getString(JsonObjectBuilderImpl.java:199)
	at org.openstreetmap.josm.plugins.mapillary.downloads.MapillaryTrafficSignDownloaderThread.run(MapillaryTrafficSignDownloaderThread.java:70)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)