Private static final long Serialversionuid

Serialversionuid is used to indicate compatibility between different versions of a class. If you modify this class, you want to modify this value. Otherwise, an error occurs when a class that was previously serialized with the old version of the class is restored. In order to ensure compatibility of the class version when deserializing, it is a good idea to add the private static final long Serialversionuid attribute to each class you want to serialize, specifying the value yourself.
You can add it automatically by clicking the left button on the warning. Of course, you can also remove the warning. Settings: Window-->preferences-->java To change the setting of the serializable class without serialversionuid from warning to ignore. Eclipse then compiles the program and the warning messages disappear.