JXTree renderer

[homebeaver]

Weil in
StringValue sv = (Object value) -> { ...
auf value==null nicht abgefangen wurde, bekomme ich diesen Tracelog:

java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "value" is null
	at io.homebeaver.gossip.TreeMaintenancePanel$1.lambda$0(TreeMaintenancePanel.java:138)
	at org.jdesktop.swingx.renderer.ComponentProvider.getValueAsString(ComponentProvider.java:287)
	at org.jdesktop.swingx.renderer.LabelProvider.format(LabelProvider.java:116)
	at org.jdesktop.swingx.renderer.ComponentProvider.configureContent(ComponentProvider.java:332)
	at org.jdesktop.swingx.renderer.ComponentProvider.getRendererComponent(ComponentProvider.java:182)
	at org.jdesktop.swingx.renderer.WrappingProvider.getRendererComponent(WrappingProvider.java:285)
	at org.jdesktop.swingx.renderer.WrappingProvider.getRendererComponent(WrappingProvider.java:48)
	at org.jdesktop.swingx.renderer.DefaultTreeRenderer.getTreeCellRendererComponent(DefaultTreeRenderer.java:138)
	at org.jdesktop.swingx.JXTree$DelegatingRenderer.getTreeCellRendererComponent(JXTree.java:1403)
	at io.homebeaver.gossip.TreeMaintenancePanel$1$1.getTreeCellRendererComponent(TreeMaintenancePanel.java:155)
	at java.desktop/javax.swing.plaf.basic.BasicTreeUI$NodeDimensionsHandler.getNodeDimensions(BasicTreeUI.java:3223)
	at java.desktop/javax.swing.tree.AbstractLayoutCache.getNodeDimensions(AbstractLayoutCache.java:497)
	at java.desktop/javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.updatePreferredSize(VariableHeightLayoutCache.java:1344)
	at java.desktop/javax.swing.tree.VariableHeightLayoutCache.rebuild(VariableHeightLayoutCache.java:723)
	at java.desktop/javax.swing.tree.VariableHeightLayoutCache.treeStructureChanged(VariableHeightLayoutCache.java:629)
	at java.desktop/javax.swing.plaf.basic.BasicTreeUI$Handler.treeStructureChanged(BasicTreeUI.java:4407)
	at java.desktop/javax.swing.tree.DefaultTreeModel.fireTreeStructureChanged(DefaultTreeModel.java:616)
	at java.desktop/javax.swing.tree.DefaultTreeModel.nodeStructureChanged(DefaultTreeModel.java:400)
	at java.desktop/javax.swing.tree.DefaultTreeModel.setRoot(DefaultTreeModel.java:150)