Currently, users have to put the full class path for configuration. Allowing users to just use the class names for all the default classes is much friendlier.

// Compare: 
processor.chain=com.mongodb.kafka.connect.mongodb.processor.DocumentIdAdder,com.mongodb.kafka.connect.mongodb.processor.BlacklistValueProjector

// To:
processor.chain=DocumentIdAdder,BlacklistValueProjector

Note: Users would still be able to use their own full path configuration.