This mechanism is sensitive to many details including fields in your class, their access modifier, the interface they implement and even different Compiler implementations, any change on a class or using a different compiler may result in different SerialVersionUID, which many eventually stop reloading serialized data. Why use SerialVersionUID in Java? ExampleĪs I said, when we don't declare SerialVersionUID, as a static, final and long value in our class, the Serialization mechanism creates it for us. Similar to Concurrency and Multi-threading, Serialization is another topic, which deserve couple of reading.

If you are new to serialization, you can also see Top 10 Java Serialization Interview question to gauge your knowledge and find gap in your understanding for further reading. In this article, we will learn about why we should use SerialVersionUID in Java and How to use serialver JDK tool for generating this ID. One quick solution to fix this problem is copying SerialVersionUID and declaring them as a private static final long constant in your class. If during de-serialization, SerialVersionUID doesn't match then the process will fail with InvalidClassException as Exception in thread 'main' java.io.InvalidClassException, also printing class-name and respective SerialVersionUID. This version number is known as SerialVersionUID in Java. When you declare a class as Serializable by implementing marker interface java.io.Serializable, Java runtime persists an instance of that class into a disk by using default Serialization mechanism, provided you have not customized the process using Externalizable interface.ĭuring serialization, Java runtime creates a version number for a class, so that it can de-serialize it later.

Java serialization data version 5