What is the usage of the field serialVersionUID (Java Serial Version Id) in Java ?

Java Serial Unique Identifier (or serialVersionUID) is used for versioning of Java Classes. Whenever you perform validation it is recommended that you declare value of serialVersionUID manually (Otherwise Java creates it on it's own while compiling). This ensures that if we make any changes in the Java class, we could avoid a "ClassNotCompatibleError" during runtime while de-serializing the class.