SerialVersionUID in Java

In this post, we will see more details on SerialVersionUID and also issues with default serial version id.

Java uses serialVersionUID field for versionsing.
It’s a static and final field of type long
JVM uses serialVersionUID to verify that the class being deserialized is compatible with the class that was used to serialize the object.
When a class is serialized, a serialVersionUID value is generated by the serialization mechanism based on the class’s structure.
In deserialization, the deserialized class is compared to the serialized class based on the serialVersionUID values. If they don’t match, a InvalidClassException is thrown.
Add private static final long field with a specific value to set the serialVersionUID for a class
It is best practice to update the serialVersionUID value every time a change is made to the class that would affect its serialization. This helps to ensure that the deserialization process will work as expected when using different versions of the class.

Default SerialVersionUID

In java , the default serialVersionUID is generated based on the class’s structure with fields: class Name, fields, and inheritance hierarchy.
If we made any changes to that class then it will affects class structure. As a result default serialVersionUID value will be different, Hence deserialization will fail with a InvalidClassException.
it is very important to explicitly set the serialVersionUID value for a class that is going to be serialized especially if it is part of a public API or if you expect it to be used for a long time.
you can control the versioning of the class and ensure compatibility between different versions of the class by setting serialVersionUID explicitly

Thanks for Reading..