Here's a fun fact. Eclipse has some seriously long class names in the bundles that come with a run-of-the-mill install.
The longest single class name is
org.sat4j.pb.constraints.CompetResolutionPBMixedHTClauseCardConstrDataStructure, or 54 characters of goodness. If you include inner classes as well, then JDT's
ConfigureWorkingSetAssignementAction$WorkingSetModelAwareSelectionDialog$GrayedCheckModelElementSorter (102) and JDT's
Perhaps these classes were implemented before the refactoring support was finished? In the words of Uncle Bob Martin, “What were they thinking ... ”