This list of frequently asked questions is compiled from several questions we have seen several times on the ImageJ forum. It will be updated as questions appear there.
Various java.lang.NoClassDefFoundErrors upon execution.
These errors may popup when you try to launch TrackMate, or plot features. A stack trace will show in the console and the second line will resemble this:
Exception in thread "TrackMate plot spot features thread" java.lang.NoClassDefFoundError: com/itextpdf/text/DocumentException at fiji.plugin.trackmate.features.SpotFeatureGrapher.render(SpotFeatureGrapher.java:115) at fiji.plugin.trackmate.gui.GrapherPanel.plotSpotFeatures(GrapherPanel.java:189) at fiji.plugin.trackmate.gui.GrapherPanel.access$100(GrapherPanel.java ...
This kind of error is caused when a Java class is missing in your installation. In most cases, this happens because your Fiji installation did not update properly. Possible solutions are