NoClassDefFoundError: javax/activation/MimetypesFileTypeMap

[naoliv]

While clicking at this nice yellow gear icon:

I am seeing this:

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (19) of main
java.lang.NoClassDefFoundError: javax/activation/MimetypesFileTypeMap
	at org.openstreetmap.josm.plugins.scripting.model.JSR223ScriptEngineProvider.<init>(JSR223ScriptEngineProvider.java:67)
	at org.openstreetmap.josm.plugins.scripting.model.JSR223ScriptEngineProvider.getInstance(JSR223ScriptEngineProvider.java:60)
	at org.openstreetmap.josm.plugins.scripting.preferences.ScriptEnginesConfigurationPanel.buildScriptEnginesInfoPanel(ScriptEnginesConfigurationPanel.java:216)
	at org.openstreetmap.josm.plugins.scripting.preferences.ScriptEnginesConfigurationPanel.buildScriptEnginesPanel(ScriptEnginesConfigurationPanel.java:318)
	at org.openstreetmap.josm.plugins.scripting.preferences.ScriptEnginesConfigurationPanel.build(ScriptEnginesConfigurationPanel.java:328)
	at org.openstreetmap.josm.plugins.scripting.preferences.ScriptEnginesConfigurationPanel.<init>(ScriptEnginesConfigurationPanel.java:208)
	at org.openstreetmap.josm.plugins.scripting.preferences.PreferenceEditor.addGui(PreferenceEditor.java:40)
	at org.openstreetmap.josm.gui.preferences.PreferenceTabbedPane.stateChanged(PreferenceTabbedPane.java:592)
	at java.desktop/javax.swing.DefaultSingleSelectionModel.fireStateChanged(DefaultSingleSelectionModel.java:143)
	at java.desktop/javax.swing.DefaultSingleSelectionModel.setSelectedIndex(DefaultSingleSelectionModel.java:74)
	at java.desktop/javax.swing.JTabbedPane.setSelectedIndexImpl(JTabbedPane.java:622)
	at java.desktop/javax.swing.JTabbedPane.setSelectedIndex(JTabbedPane.java:597)
	at java.desktop/javax.swing.plaf.basic.BasicTabbedPaneUI$Handler.mousePressed(BasicTabbedPaneUI.java:4086)
	at java.desktop/java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:287)
	at java.desktop/java.awt.Component.processMouseEvent(Component.java:6586)
	at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
	at java.desktop/java.awt.Component.processEvent(Component.java:6354)
	at java.desktop/java.awt.Container.processEvent(Container.java:2261)
	at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4966)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2319)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4798)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4914)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4540)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4484)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2305)
	at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4798)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
	at java.desktop/java.awt.EventQueue.access$600(EventQueue.java:97)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:117)
	at java.desktop/java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:190)
	at java.desktop/java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:235)
	at java.desktop/java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:233)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.desktop/java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:233)
	at java.desktop/java.awt.Dialog.show(Dialog.java:1070)
	at java.desktop/java.awt.Component.show(Component.java:1674)
	at java.desktop/java.awt.Component.setVisible(Component.java:1621)
	at java.desktop/java.awt.Window.setVisible(Window.java:1031)
	at java.desktop/java.awt.Dialog.setVisible(Dialog.java:1005)
	at org.openstreetmap.josm.gui.preferences.PreferenceDialog.setVisible(PreferenceDialog.java:143)
	at org.openstreetmap.josm.actions.PreferencesAction.run(PreferencesAction.java:112)
	at org.openstreetmap.josm.actions.PreferencesAction.actionPerformed(PreferencesAction.java:101)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
	at java.desktop/javax.swing.AbstractButton.doClick(AbstractButton.java:369)
	at java.desktop/javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:980)
	at java.desktop/javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1024)
	at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297)
	at java.desktop/java.awt.Component.processMouseEvent(Component.java:6589)
	at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
	at java.desktop/java.awt.Component.processEvent(Component.java:6354)
	at java.desktop/java.awt.Container.processEvent(Container.java:2261)
	at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4966)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2319)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4798)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4914)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4543)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4484)
	at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2305)
	at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)
	at java.desktop/java.awt.Component.dispatchEvent(Component.java:4798)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
	at java.desktop/java.awt.EventQueue.access$600(EventQueue.java:97)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
	at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
Caused by: java.lang.ClassNotFoundException: javax.activation.MimetypesFileTypeMap
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:466)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:566)
	at org.openstreetmap.josm.plugins.PluginClassLoader.loadClass(PluginClassLoader.java:74)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
	... 94 more

The scripting plugin is version 30787 and JOSM is 14221
Tell me if you need any more info, please.

[Gubaer]

A similar issue has been reported as JOSM ticket 15490.

Try to start JOSM with the command line option --add-modules=java.activation, if you use Java9.

@don-vip writes in 15490, that starting from Java 11 this will not work anymore. I'll try to find a solution for Java 11 later.

[Gubaer]

Plugin release 30791 now includes a standalone version of javax.activation.

You have to upgrade to at least JOSM 14256 and update the plugin in the preferences dialog. Plugin releases built for older JOSM version don't include this fix.