Strange warning installing plugin

[skyper]

What steps will reproduce the problem?

1. start JOSM for the first time
2. install plugin (I used utilsplugin2 but have seen this warning with other plugins, too)

What is the expected result?

No warning

What happens instead?

strange warning on the console but plugin works

2016-12-31 14:13:27.628 INFO: Downloading Plugin utilsplugin2...
2016-12-31 14:13:28.011 INFO: GET https://svn.openstreetmap.org/applications/editors/josm/dist/utilsplugin2.jar -> 200 (319 kB)
2016-12-31 14:13:28.936 WARNING: Invalid jar file ''/home/gast/.local/share/JOSM/plugins/utilsplugin2.jar.new'' (exists: false, canRead: false)
2016-12-31 14:13:31.499 INFO: loading plugin 'utilsplugin2' (version 33088)

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

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2016-12-31 00:04:03 +0100 (Sat, 31 Dec 2016)
Build-Date:2016-12-31 02:32:34
Revision:11421
Relative:URL: ^/trunk

Identification: JOSM/1.5 (11421 en) Linux Debian GNU/Linux 8.6 (jessie)
Memory Usage: 384 MB / 882 MB (277 MB allocated, but free)
Java version: 1.8.0_111-8u111-b14-2~bpo8+1-b14, Oracle Corporation, OpenJDK 64-Bit Server VM
Java package: openjdk-8-jre:amd64-8u111-b14-2~bpo8+1
Java ATK Wrapper package: libatk-wrapper-java:all-0.30.4-3
Program arguments: [--language=en]

Plugins:
+ utilsplugin2 (33088)

Last errors/warnings:
- W: Invalid jar file ''<josm.userdata>/plugins/utilsplugin2.jar.new'' (exists: false, canRead: false)

[Don-vip]

Closed as duplicate of #17881.