Unable to save session with WMTS layers

[anonymous]

What steps will reproduce the problem?

1. Download some data
2. Add WMTS imagery layer
3. Modify some data
4. Try to close JOSM
5. In dialog choose "Save session as"
6. Error

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

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2015-10-31 02:32:27
Last Changed Author: Don-vip
Revision: 8971
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Relative URL: ^/trunk
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2015-10-31 01:32:04 +0100 (Sat, 31 Oct 2015)
Last Changed Rev: 8971

Identification: JOSM/1.5 (8971 pl) Linux Ubuntu 15.10
Memory Usage: 374 MB / 869 MB (143 MB allocated, but free)
Java version: 1.7.0_85, Oracle Corporation, OpenJDK 64-Bit Server VM
Java package: openjdk-7-jre:amd64-7u85-2.6.1-5ubuntu0.15.10.1
VM arguments: [-Djosm.home=/home/myhomedir/.josm2]
Dataset consistency test: No problems found

Plugins:
- PicLayer (31694)
- measurement (31694)
- reverter (31694)
- tageditor (31615)
- utilsplugin2 (31694)

Last errors/warnings:
- E: java.lang.RuntimeException: java.lang.NoSuchMethodException: org.openstreetmap.josm.io.session.ImagerySessionExporter.<init>(org.openstreetmap.josm.gui.layer.WMTSLayer). Przyczyna: java.lang.NoSuchMethodException: org.openstreetmap.josm.io.session.ImagerySessionExporter.<init>(org.openstreetmap.josm.gui.layer.WMTSLayer)

java.lang.RuntimeException: java.lang.NoSuchMethodException: org.openstreetmap.josm.io.session.ImagerySessionExporter.<init>(org.openstreetmap.josm.gui.layer.WMTSLayer)
	at org.openstreetmap.josm.io.session.SessionWriter.getSessionLayerExporter(SessionWriter.java:80)
	at org.openstreetmap.josm.actions.SessionSaveAsAction$SessionSaveAsDialog.initialize(SessionSaveAsAction.java:200)
	at org.openstreetmap.josm.actions.SessionSaveAsAction$SessionSaveAsDialog.<init>(SessionSaveAsAction.java:181)
	at org.openstreetmap.josm.actions.SessionSaveAsAction.saveSession(SessionSaveAsAction.java:86)
	at org.openstreetmap.josm.gui.io.SaveLayersDialog$SaveSessionAction.actionPerformed(SaveLayersDialog.java:375)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
	at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
	at java.awt.Component.processMouseEvent(Component.java:6516)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3312)
	at java.awt.Component.processEvent(Component.java:6281)
	at java.awt.Container.processEvent(Container.java:2229)
	at java.awt.Component.dispatchEventImpl(Component.java:4872)
	at java.awt.Container.dispatchEventImpl(Container.java:2287)
	at java.awt.Component.dispatchEvent(Component.java:4698)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
	at java.awt.Container.dispatchEventImpl(Container.java:2273)
	at java.awt.Window.dispatchEventImpl(Window.java:2719)
	at java.awt.Component.dispatchEvent(Component.java:4698)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:747)
	at java.awt.EventQueue.access$300(EventQueue.java:103)
	at java.awt.EventQueue$3.run(EventQueue.java:706)
	at java.awt.EventQueue$3.run(EventQueue.java:704)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.awt.EventQueue$4.run(EventQueue.java:720)
	at java.awt.EventQueue$4.run(EventQueue.java:718)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:717)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:154)
	at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:182)
	at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:221)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:219)
	at java.awt.Dialog.show(Dialog.java:1082)
	at java.awt.Component.show(Component.java:1655)
	at java.awt.Component.setVisible(Component.java:1607)
	at java.awt.Window.setVisible(Window.java:1014)
	at java.awt.Dialog.setVisible(Dialog.java:1005)
	at org.openstreetmap.josm.Main.saveUnsavedModifications(Main.java:1054)
	at org.openstreetmap.josm.Main.saveUnsavedModifications(Main.java:1023)
	at org.openstreetmap.josm.Main.exitJosm(Main.java:1074)
	at org.openstreetmap.josm.gui.MainApplication$1.windowClosing(MainApplication.java:111)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349)
	at java.awt.Window.processWindowEvent(Window.java:2051)
	at javax.swing.JFrame.processWindowEvent(JFrame.java:290)
	at java.awt.Window.processEvent(Window.java:2009)
	at java.awt.Component.dispatchEventImpl(Component.java:4872)
	at java.awt.Container.dispatchEventImpl(Container.java:2287)
	at java.awt.Window.dispatchEventImpl(Window.java:2719)
	at java.awt.Component.dispatchEvent(Component.java:4698)
...<snip>...

[simon04]

Relates to r8620.

[simon04]

In 9001/josm:

fix #12088 - Unable to save session with WMTS layers