| class  | DatabaseClosedException | db4o-specific exception. | 
| class  | DatabaseFileLockedException | db4o-specific exception.
 this Exception is thrown during any of the db4o open calls
 if the database file is locked by another process.
 | 
| class  | Db4oFileHeaderCorruptionException |  | 
| class  | Db4oIOException | db4o-specific exception.
 This exception is thrown when a system IO exception
 is encounted by db4o process.
 | 
| class  | EmergencyShutdownReadOnlyException | A previous IO exception has switched the database file
 to read-only mode for controlled shutdown. | 
| class  | IncompatibleFileFormatException | db4o-specific exception.
 This exception is thrown when the database file format
 is not compatible with the applied configuration.
 | 
| class  | OldFormatException |  | 
| class  | UnsupportedOldFormatException | This exception is thrown while reading old database
 files for which support has been dropped. |