Devs, Please be careful with how you are serializing internal classes between servers and clients. While you may think you are safe if you simply use DataSerializable you are wrong, very very wrong. If you define your internal class as DataSerializable then when serialized the fully qualified class name is serialized ahead of it to identify the class being serialized. This happens because there is no Instantiator for your internal class, so it can’t use a number and falls back to the class name. If you rename or move the class later you will run into backwards compatibility issues that have to be resolved by transforming the string name back and forth to the new name.
DataSerializable should be reserved only for user defined classes. Please use DataSerializableFixedID for internal classes. This method uses a fixed integer to identify your class. Not only is it more efficient it also avoids issues with class or package renaming. Thanks, Jake
