What means 1L serialVersionUID? When could I use this default value 1L?

Question

There are 3 ways to define the serialVersionUID :

1. private static final long serialVersionUID = 1L; (Default)
2. private static final long serialVersionUID = -         


        

Answer 1

This is explain here:

The serialVersionUID is a universal version identifier for a Serializable class. Deserialization uses this number to ensure that a loaded class corresponds exactly to a serialized object. If no match is found, then an InvalidClassException is thrown.

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From the javadoc:

The serialization runtime associates with each serializable class a version number, called a serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization. If the receiver has loaded a class for the object that has a different serialVersionUID than that of the corresponding sender's class, then deserialization will result in an InvalidClassException. A serializable class can declare its own serialVersionUID explicitly by declaring a field named "serialVersionUID" that must be static, final, and of type long:

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Useful Links

1. java.io.Serializable
2. Why should I bother about serialVersionUID? (StackOverflow)
3. serialVersionUID in Java Serialization